KR102542850B1 - Antibacterial nonwoven polyamide with zinc content - Google Patents

Abstract

less than 4000 ppm zinc dispersed in non-woven polyamide fibers; and non-woven polyamide fibers comprising less than 2000 ppm phosphorus. the fibers have an average fiber diameter of less than 25 microns; The polyamide structure exhibits a Staphylococcus aureus reduction of greater than 90% as measured by ISO 20743-13.

Description

Antibacterial nonwoven polyamide with zinc content

The present invention relates to a non-woven polyamide having permanent antimicrobial properties. In particular, the present invention relates to an antimicrobial nonwoven polyamide comprising a unique antimicrobial component(s).

CROSS REFERENCES TO RELATED APPLICATIONS

This application is related to and claims priority to US Provisional Patent Application Serial No. 62/781,233, filed on December 18, 2018, which is incorporated herein by reference.

There is increasing interest in fabrics with antibacterial properties. In some cases, a number of treatments or coatings are applied to the fabric to impart antibacterial properties to the fabric. Compounds containing copper, silver, gold or zinc individually or in combination are useful in this application to effectively combat pathogens such as bacteria, mold, mildew, viruses, spores and fungus. was used in

Antimicrobial fibers and fabrics of this type can be used in many industries, including healthcare, hospitality, military and athletics, among others. However, existing antimicrobial fibers and fabrics have difficulty meeting the many other requirements of these applications. In addition, many known antimicrobial fabrics do not have sufficient antimicrobial properties and do not retain these properties over the lifetime of the product in which they are used. In some cases, antimicrobial additives may leach out of the fabric and adversely affect the environment.

For example, in the healthcare and hospitality industries, certain fabrics must always be hygienic. To comply with these hygiene standards, fabrics are washed daily and often bleached. As another example, athletic apparel is prone to bacterial growth due to both internal and external factors, and sweat and bacteria transported through the skin can lead to bacterial growth in the fabric of the garment. In some cases, these bacteria cause unpleasant odors, stains, fabric deterioration, and even physical irritation such as skin allergies and skin infections. Thus, in many applications, repeated use and cleaning cycles are very common. Unfortunately, conventional fabrics have been found to deteriorate and lose their antimicrobial properties during repeated use and/or washing cycles.

As an example of conventional antimicrobial yarns and fabrics, US Patent No. 6,584,668 discloses a durable non-conductive metal treatment applied to yarns and textile fabrics. Durable non-conductive metal treatments are coatings or finishes applied to yarns and textile fabrics. Metal treatments may include silver and/or silver ions, zinc, iron, copper, nickel, cobalt, aluminum, gold, manganese, magnesium, and the like. The metal treatment is applied as a coating or film to the outer surface of the yarn or fabric.

Also, U.S. Patent No. 4,701,518 discloses an antibacterial nylon made using a zinc compound (ZnO) and a phosphorus compound in water to form carpet fibers. This process produces a carpet nylon fiber with 18 denier per filament (dpf) and is made by conventional melt polymerization. These carpet fibers typically have average diameters well in excess of 30 microns and are generally not suitable for next-to-skin applications.

Conventional polymer formulations, such as the aforementioned nylon formulations, are known to be difficult to process, especially when smaller fibers (and lower denier) are required, such as in nonwoven applications. For example, conventional formulations with nylon and various other additives may require higher die pressures to form smaller diameter fibers, which in turn can lead to catastrophic fiber interruption. In some cases, typical polymer formulations have viscosities that are too high for effective processing and may require adjustment, which can reduce overall efficiency.

Although some references may teach the use of antibacterial fibers and fabrics, multiple washes while maintaining fiber strength and still being efficient in processing (e.g., having relatively low viscosity and/or using lower die pressures). There is still a need for antimicrobial fibers and fabrics that retain antibacterial properties afterward.

According to some embodiments, the present invention provides a nonwoven polyamide having an average fiber diameter of less than 25 microns; less than 2000 ppm zinc dispersed in the nonwoven polyamide; and less than 2000 ppm phosphorus, wherein the weight ratio of zinc to phosphorus is at least 1.3:1, or less than 0.64:1. In some aspects, the weight ratio of zinc to phosphorus is at least 2:1. The relative viscosity of the polyamide composition may range from 10 to 100, for example from 20 to 100. In some aspects, the polyamide composition can include less than 500 ppm zinc. The polyamide composition may include a matting agent comprising at least a portion of the phosphorus. In some aspects, the polyamide composition is free of phosphorus. Zinc may be provided via zinc compounds including zinc oxide, zinc acetate, zinc ammonium carbonate, zinc ammonium adipate, zinc stearate, zinc phenyl phosphinic acid, zinc pyrithione, and/or combinations thereof. In some aspects, the zinc compound does not include zinc phenyl phosphinate and/or zinc phenyl phosphonate. In some aspects, phosphorus is provided via a phosphorus compound comprising phosphoric acid, benzene phosphinic acid, benzene phosphonic acid, manganese hypophosphite, sodium hypophosphite, monosodium phosphate, hypophosphorous acid, phosphorous acid, and/or combinations thereof. In some aspects, the polyamide composition comprises less than 500 ppm zinc, wherein the polyamide composition comprises a matting agent comprising at least a portion of the phosphorus, wherein the polyamide composition comprises 90% as measured by ISO 20743-13. More than Staphylococcus aureus ( Staphylococcus Aureus ) Represents a reduction. In some aspects, the polyamide comprises nylon, wherein the zinc is provided via zinc oxide and/or zinc pyrithione, and the polyamide composition has a relative viscosity ranging from 10 to 100, such as from 20 to 100. In some aspects, the polyamide comprises nylon-6,6, wherein the zinc is provided via zinc oxide, the weight ratio of zinc to phosphorus is at least 2:1, and the polyamide composition has a weight ratio of 90 as measured by ISO 20743-13. % or greater Staphylococcus aureus reduction. The nonwoven may further comprise one or more additional antimicrobial agents including silver, tin, copper and gold, and alloys, oxides and/or combinations thereof. The melting point of the nonwoven may be above 225°C. Nonwoven polyamides may be formed by melt spinning, solution spinning, centrifugal spinning or electrospinning. In some aspects, the average fiber diameter of the nonwoven polyamide is 1000 nanometers or less. In some aspects, no more than 20% of the fibers have a diameter greater than 700 nanometers. In some aspects, the polyamide includes nylon 66 or nylon 6/66. In some aspects, the polyamide includes high temperature nylon. In some aspects, polyamide includes N6, N66, N6T/66, N612, N6/66, N6I/66, N66/6I/6T, N11, and/or N12, where "N" refers to nylon. . In some aspects, the nonwoven polyamide has an air permeability value of less than 600 CFM/ft ² . In some aspects, the nonwoven polyamide has a basis weight of 200 GSM or less.

In some embodiments, the present invention provides less than 4000 ppm zinc, for example less than 3200 ppm, or less than 3100 ppm zinc dispersed in the nonwoven polyamide fibers; and non-woven polyamide fibers comprising less than 2000 ppm phosphorous and having antimicrobial properties, such as nylon 66 or nylon 6/66. The fibers have an average fiber diameter of less than 25 microns, such as less than 20 microns. The polyamide structure exhibits Staphylococcus aureus reduction of greater than 90% as measured by ISO 20743-13. The weight ratio of zinc to phosphorus may be at least 1.3:1, or less than 0.64:1. The relative viscosity of the polyamide composition may be less than 100. The structure and/or fibers may include a matting agent comprising at least a portion of the phosphorus. Non-woven polyamides may be melt spun, spin bonded, electrospun, solution spun or centrifugally spun. In some cases, no more than 20% of the fibers have a diameter greater than 700 nanometers. Antimicrobial fibers can have a zinc retention greater than 70% as measured by the dye bath test.

In some aspects, the present invention relates to a method of making an antimicrobial nonwoven polyamide structure having permanent antimicrobial properties, the method comprising preparing a precursor polyamide optionally comprising an aqueous monomer solution; dispersing less than 4000 ppm zinc within the precursor polyamide; dispersing less than 2000 ppm phosphorus within the precursor polyamide; polymerizing the precursor polyamide to form a polyamide composition; spinning the polyamide composition to form antimicrobial polyamide fibers; and forming the antimicrobial polyamide fibers into an antimicrobial nonwoven structure having a fiber diameter of less than 25 microns. Antimicrobial fibers can have a zinc retention greater than 70% as measured by the dye bath test. The weight ratio of zinc to phosphorus may be at least 1.3:1, or less than 0.64:1. Polyamide can be melt spun by melt blowing with a high velocity gas stream through a die. Non-woven polyamides may be melt spun, spin bonded, electrospun, solution spun or centrifugally spun. The nonwoven may include a nylon 66 polyamide melt spun into fibers and formed into the nonwoven, wherein no more than 20% of the fibers have a diameter greater than 25 microns.

According to some embodiments, the present invention provides a nonwoven polyamide having an average fiber diameter of less than 25 microns; less than 2000 ppm zinc dispersed in the nonwoven polyamide; and less than 2000 ppm phosphorus. In some aspects, the weight ratio of zinc to phosphorus is at least 1.3:1; or less than 0.64:1. In some aspects, the weight ratio of zinc to phosphorus is at least 2:1. In some aspects, the fibers have an average diameter of less than 20 microns. The nonwoven polyamide may include less than 500 ppm zinc. The nonwoven polyamide may include a matting agent comprising at least a portion of the phosphorus. Antimicrobial fibers can have a zinc retention greater than 70% as measured by the dye bath test. Zinc can be a zinc compound including zinc oxide, zinc acetate, zinc ammonium carbonate, zinc ammonium adipate, zinc stearate, zinc phenyl phosphinic acid, zinc pyrithione, and/or combinations thereof. The phosphorus can be a phosphorus compound comprising phosphoric acid, benzene phosphinic acid, benzene phosphonic acid, manganese hypophosphite, sodium hypophosphite, monosodium phosphate, hypophosphorous acid, phosphorous acid, and/or combinations thereof. The nonwoven polyamide may comprise less than 500 ppm zinc, wherein the polymer comprises a matting agent comprising at least a portion of said phosphorus, and wherein the antimicrobial fiber exhibits a Staphylococcus aureus reduction of at least 90% as measured by ISO 20743-13. . The non-woven polyamide may comprise nylon, wherein the zinc is provided in the form of zinc oxide and/or zinc pyrithione, and the polymeric resin composition has a relative viscosity in the range of 10 to 100, such as 20 to 100, and is antimicrobial. The fibers have a zinc retention greater than 80% as measured by the dye bath test, and the fibers have an average diameter of less than 18 microns. The non-woven polyamide may include nylon-6,6, the zinc provided in the form of zinc oxide, a zinc to phosphorus weight ratio of at least 2:1, and the antimicrobial fiber having a weight ratio of at least 90% as measured by ISO 20743-13. Staphylococcus aureus reduction, the antimicrobial fibers have a zinc retention greater than 95% as measured by the dye bath test, and the antimicrobial fibers have an average diameter of less than 10 microns. The nonwoven polyamide may further comprise one or more additional antimicrobial agents including silver, tin, copper and gold, and alloys, oxides and/or combinations thereof. The melting point of the nonwoven may be above 225°C. Non-woven polyamides may be melt spun, spin bonded, electrospun, solution spun or centrifugally spun. In some aspects, the average fiber diameter of the nonwoven polyamide can be 1000 nanometers or less. In some aspects, no more than 20% of the fibers have a diameter greater than 700 nanometers. Polyamides may include nylon 66 or nylon 6/66. Polyamides may include high temperature nylons. Polyamides may include N6, N66, N6T/66, N612, N6/66, N6I/66, N66/6I/6T, N11 and/or N12, where "N" refers to nylon. Nonwoven polyamides can have an air permeability value of less than 600 CFM/ft ² . The nonwoven polyamide may have a basis weight of 200 GSM or less. Basis weight is determined by ASTM D-3776 and is reported as GSM (g/m ² ).

According to some aspects, the present invention relates to a method of making an antimicrobial nonwoven polyamide having permanent antibacterial properties, the method comprising preparing an aqueous monomer solution to form a polyamide; adding less than 1000 ppm of zinc dispersed in the aqueous monomer solution; adding less than 2000 ppm phosphorus; polymerizing the aqueous monomer solution to form polyamide; spinning the polyamide to form antimicrobial polyamide fibers; and forming the antimicrobial polyamide fibers into an antimicrobial nonwoven polyamide having a fiber diameter of less than 25 microns, wherein the weight ratio of zinc to phosphorus is at least 1.3:1, or less than 0.64:1. The polyamide may contain less than 2000 ppm zinc. Antimicrobial fibers may have a zinc retention of greater than 70% as measured by the dye bath test. Adding phosphorus may include adding a matting agent containing at least a portion of the phosphorus. Polyamides can be melt spun by melt blowing with a high velocity gas stream through a die. Polyamides may be melt spun by two-phase propellant gas spinning, which involves extruding the polyamide composition in liquid form with pressurized gas through fiber-forming channels. Nonwovens may be formed by collecting fibers on a moving belt. In some aspects, the relative viscosity of the polyamide in the nonwoven can be reduced compared to the polyamide prior to spinning and forming the nonwoven. In some aspects, the relative viscosity of the polyamide in the nonwoven is the same or increased compared to the polyamide prior to spinning and forming the nonwoven. The nonwoven may include a nylon 66 polyamide that is melt spun and formed into the nonwoven, wherein the nonwoven has a TDI of at least 20 ppm and an ODI of at least 1 ppm. The nonwoven may include a nylon 66 polyamide melt spun into fibers and formed into the nonwoven, wherein no more than 20% of the fibers have a diameter greater than 25 microns. In some aspects, the polyamide is melt spun, spinbonded, electrospun, solution spun or centrifugally spun.

In some embodiments, the present invention provides nonwoven polyamide fibers having an average fiber diameter of less than 25 microns; and less than 4000 ppm zinc dispersed within the non-woven polyamide fibers. The polyamide composition can exhibit greater than 90% Staphylococcus aureus reduction as measured by ISO 20743-13.

In some embodiments, the present invention relates to a method of making an antimicrobial nonwoven polyamide structure having antimicrobial properties, the method comprising a polyamide, less than 4000 ppm zinc dispersed in the polyamide and 2000 ppm dispersed in the polyamide. preparing a formulation comprising a polyamide comprising less than phosphorus; spinning the formulation to form antimicrobial polyamide fibers having a fiber diameter of less than 25 microns; and forming the antimicrobial polyamide fibers into an antimicrobial non-woven polyamide structure. Fibers can be spun using a die pressure of less than 275 psig.

The invention is described in detail below with reference to the drawings, wherein like numbers indicate like parts in the drawings.
1 and 2 are separate schematic diagrams of a two-phase propellant-gas firing system useful in connection with the present invention.
3 is a photomicrograph of nanofiber nylon 66 melt-spun into a nonwoven with an RV of 7.3 at 50X magnification.
FIG. 4 is a photomicrograph of nanofibers of the grade of FIG. 3 of nylon 66 melt spun into a nonwoven with an RV of 7.3 at a magnification of 8000X.
5 is a schematic diagram of a meltblowing process related to an aspect of the present invention.
6 is a photomicrograph of nylon 66 nanofibers with an RV of 36 at 100X magnification.
7 is a graph comparing thermal degradation index and oxidative degradation index values for nanofiber samples as a function of die temperature.
8 is a graph comparing thermal degradation index and oxidative degradation index values for nanofiber samples as a function of meter pump speed.

Introduction

As discussed above, some conventional antimicrobial fibers and fabrics utilize antimicrobial compounds to inhibit pathogens. For example, some fabrics may include an antimicrobial additive, such as silver, applied as a film on the outer layer by a topical treatment. However, these treatments have often been found to (quickly) leach out of the fabric. Likewise, in some non-coating applications where the antimicrobial additive is a component of the fabric, it is known that the antimicrobial additive is usually washed in about 10 wash cycles to leach the additive into the environment.

However, the disclosed nonwoven fibers and fabrics advantageously eliminate the need for topical treatment to render the garment antimicrobial. The antimicrobial fibers and fabrics of the present invention have “built-in” antimicrobial properties. And, these properties are advantageously not washed out even after significant washing or washing cycles. In addition, antimicrobial fibers can maintain fastness (a characteristic related to a material's resistance to color fading or running) and durability. Unlike conventional antimicrobial fabrics, the fibers and fabrics of the present invention do not lose their antimicrobial activity due to leaching and extraction after repeated use and washing cycles.

References related to carpet fibers also relate to higher denier (eg greater than 12 dpf) and/or higher fiber diameter (eg greater than 20 micron) fibers/filaments. These carpet fibers are formed via entirely different, non-similar processes/equipment (filament spinning vs. fiber blowing), which give a completely different product (single longer, thicker filament vs. multiple thinner, interwound fibers). Given these important differences, the teachings of these carpet fiber references are typically not considered relevant to blowing operations (eg, nonwovens). More specifically, in carpet fiber production, formulations with different amounts, eg higher amounts, of phosphorus compounds (optionally together with zinc compounds) are used for their ability to increase the relative viscosity of the polymer.

However, phosphorus compounds are typically not used in non-carpet, eg textile polymer formulations, as their use and accompanying build-up of relative viscosity can contribute to processability problems. In other words, nonwoven equipment and processes cannot process carpet formulations (with increased relative viscosities) as this can hinder processability and make production difficult, if not impossible. Unlike carpet formulations, the (non-woven) polyamide compositions disclosed herein include a unique combination of zinc and optionally phosphorus, each of which preferably retards or eliminates viscosity build-up associated with conventional carpet fiber formulations. Include in a specific amount, eg a lower amount (which also provides an additional synergistic benefit). As a result, the nonwoven formulations disclosed herein surprisingly can form much thinner fibers with antimicrobial properties, for example in the form of nonwoven webs, without the aforementioned processing problems. Conventional formulations cannot be effectively spun into such thin diameter fibers, eg, nanofibrous nonwoven webs.

Additionally, conventional nylon formulations using antimicrobial agents may require the use of higher die pressures to form smaller diameter nonwoven mat fibers. These higher die pressures often lead to higher critical fiber breaks.

In addition, some references have directly mixed antimicrobial agents with fibers, leather, or plastics, but these processes do not solve the problem of deterioration in product quality because antibacterial activity is lost due to thermal decomposition, color fastness degradation, or elution of antibacterial substances. did Other conventional antimicrobial fabrics, such as, for example, non-woven fabrics, have been found to be insufficiently strong for apparel applications (eg, unable to withstand significant washing) and unable to retain antimicrobial properties over the life of the product.

In addition, the presence of zinc (a zinc compound) and optionally phosphorus (each preferably in certain amounts in the nonwoven polyamide composition) will provide effective production of antimicrobial nonwoven fibers, such as nanofibers, capable of maintaining durable antibacterial properties. It turned out that you can Production of these fibers can advantageously be achieved using lower die pressure operations. In some cases, the composition has a lower relative viscosity (RV) that can contribute to lower die pressure operation. Without wishing to be bound by theory, in some embodiments, the use of certain amounts of phosphorus compounds may allow zinc to be more stably disposed in polymers and/or fibers, thus preventing removal from fibers/fabrics, for example, during laundering. It can delay the leaching of zinc. In other words, the polyamide composition may have certain amounts of zinc and phosphorus embedded in the polyamide to maintain permanent antibacterial properties. It has also been found that the use of nonwoven polyamides as polymer resins, particularly nonwoven polyamides formed by melt spinning, solution spinning, centrifugal spinning or electrospinning processes, have improved durability. As further described herein, there are many additional advantages to using meltblown or spun nonwoven polyamides.

It is also beneficial that providing a zinc compound and optionally a phosphorus compound to the polymer composition during the production process of the fibers, for example in an aqueous monomer solution or via a masterbatch, results in fibers having the antimicrobial agent evenly dispersed throughout the entire fiber. Turns out. In a conventional process, a silver coating is applied to the outer surface of a fabric to impart antimicrobial properties to the fabric. However, silver coatings do not disperse throughout the fabric and are prone to leaching components, such as silver, into the environment. Advantageously, the present polymer composition does not cause toxicity as it does not elute the antimicrobial agent and does not contain any toxic components such as silver for example. Additionally, antimicrobial fibers formed from the present polymeric composition do not require a separate application step because the antimicrobial agent is permanently located in the polymer and/or fiber.

In another aspect, the composition contains little or no phosphorus. Optionally, the disclosed zinc compounds in the disclosed amounts provide beneficial properties for antimicrobial polyamide compositions and processes using them, eg, low die pressure operation.

As noted above, as an added benefit, fibers formed using the nonwoven polyamide formulations/compositions have advantageous physical characteristics, such as lower average fiber diameters, which are suitable for a variety of applications where higher fiber diameters are unsuitable, such as Allows for use in clothing or other skin contact applications and filtration where thick fibers are unsuitable.

In one aspect, the present invention relates to polyamide formulations/compositions that can be used in some cases to form antimicrobial fibers (nanofibres) that are optionally arranged to form a polyamide structure. The nonwoven polyamide composition includes certain antimicrobial agents that are efficacious and highly resistant to washing or abrasion from the fibers. Importantly, the formulation provides processing advantages, such as the ability to form thinner diameter fibers, the ability to be used in low die pressure operation, and/or the ability to have desirable relative viscosity (RV) parameters. In one aspect, the antimicrobial fibers form a fabric or specific part of a fabric. In some embodiments, the formulation includes a polyamide or mixture of polyamides and a zinc compound. In some cases, the formulation further includes a phosphorus compound. Details of the components (and their compositional amounts), items formed therefrom and their performance characteristics are disclosed herein.

In some aspects, the present invention relates to non-woven polyamide structures, such as mats, having antimicrobial properties. The structure includes, for example, thin diameter polyamide fibers (in some cases non-woven fibers) with an average fiber diameter of less than 25 microns. Fibers contain certain amounts of zinc compounds, and zinc is dispersed within the fibers (as a component of the fibers/polymers), in contrast to conventional fibers or structures which may have an antimicrobial coating on their surface.

The structure (and/or fibers forming the structure) has improved antibacterial performance, e.g., the structure has a Staphylococcus aureus reduction of at least 90%, such as at least 99%, or at least 90% as measured by ISO 20743-13; eg at least 99% or greater Klebsiella pneumoniae growth reduction.

antibacterial ingredient

As noted above, the polyamide formulation preferably includes zinc and optionally phosphorus in certain amounts in the polyamide composition, which provides the antimicrobial benefits and/or physical/performance benefits described above. As used herein, “zinc compound” refers to a compound having one or more zinc molecules or ions. As used herein, “phosphorus compound” refers to a compound having one or more phosphorus molecules or ions.

The polyamide formulation (or structure or fibers made therefrom) comprises (elemental) zinc, for example zinc is dispersed within the polyamide formulation. In some embodiments, the concentration of zinc in the polyamide formulation is between 100 ppb and 4000 ppm, e.g., 500 ppb and 3500 ppm, 1 ppm and 3500 ppm, 200 ppm and 3000 ppm, 275 ppm and 3100 ppm, 200 ppm and 1500 ppm, 100 ppm and 2000 ppm, 2 00ppm to 700ppm, 250ppm to 550 ppm, 1 ppm to 1000 ppm, such as 25 ppm to 950 ppm, 50 ppm to 900 ppm, 100 ppm to 800 ppm, 150 ppm to 700 ppm, 175 ppm to 600 ppm, 200 ppm to 500 ppm, 215 ppm to 400 ppm, 22 5 ppm to 350 ppm, or 250 ppm to 300 ppm. In terms of the lower limit, the polyamide formulation contains greater than 100 ppb zinc, e.g. greater than 500 ppb, greater than 1 ppm, greater than 5 ppm, greater than 10 ppm, greater than 25 ppm, greater than 50 ppm, greater than 75 ppm, greater than 100 ppm, greater than 150 ppm, greater than 175 ppm, greater than 200 ppm, greater than 215 ppm, greater than 225 ppm, greater than 250 ppm or greater than 275 ppm zinc. In terms of upper limits, a polyamide formulation may contain less than 4000 ppm zinc, such as less than 3500 ppm, less than 3000 ppm, less than 3100 ppm, less than 2000 ppm, less than 1500 ppm zinc, less than 1000 ppm zinc, less than 950 ppm, less than 900 ppm, less than 800 ppm, less than 700 ppm, 600 ppm less than 550 ppm, less than 500 ppm, less than 400 ppm or less than 300 ppm zinc. In some aspects, zinc is embedded in the polymer formed from the polyamide formulation.

The manner in which zinc is provided to the polyamide formulation can vary widely. Many techniques for providing zinc to polyamide formulations are within the contemplation of this invention and would be suitable. As an example, a zinc compound may be added as a component of polyamide. In one aspect, the zinc compound may be added as a master batch. The master batch may include a polyamide such as nylon 6 or nylon 6,6. In another aspect, the zinc compound may be added by dusting the powder onto pellets. In another embodiment, zinc can be added (as a powder) to nylon 6,6 pellets and processed through a twin screw extruder to more evenly distribute the material through the polymer to improve the uniformity of the additive throughout the fabric. In one aspect, a zinc compound may be added to the salt solution during polyamide formation.

In some embodiments, the formulation, structure and/or fiber comprises (elemental) phosphorus. Regardless of how phosphorus is provided (see discussion below), phosphorus, like zinc, is present in the polyamide formulation. In some embodiments, the concentration of phosphorus in the polyamide formulation is 10 ppm to 1000 ppm, e.g., 20 ppm to 950 ppm, 30 to 900, 50 ppm to 850 ppm, 100 ppm 800 ppm, 150 ppm to 750 ppm, 200 ppm to 600 ppm, 250 ppm to 550 ppm, 30 0 ppm to 500 ppm, or It is in the range of 350 ppm to 450 ppm. In terms of upper limits, the concentration of phosphorus in the polyamide formulation may be less than 1000 ppm, such as less than 950 ppm, less than 900 ppm, less than 800 ppm, less than 700 ppm, less than 600 ppm, less than 500 ppm, less than 400 ppm, less than 300 ppm or less than 200 ppm. As a lower limit, the concentration of phosphorus in the polyamide formulation may be greater than 10 ppm, such as greater than 20 ppm, greater than 40 ppm, greater than 60 ppm, greater than 80 ppm, greater than 100 ppm, greater than 150 ppm or greater than 180 ppm. In some aspects, phosphorus is embedded in the polymer of the polyamide formulation.

The manner in which phosphorus is provided to the polyamide formulation can vary greatly. Many techniques for providing phosphorus to the polyamide formulation are within the scope of the present invention and would be suitable. As an example, phosphorus or a phosphorus compound may be added as a component of the resin, for example in a manner similar to zinc.

In one aspect, phosphorus may be provided as a component of other additives. For example, phosphorus can be a component of a matting agent added to the polymer composition. Specifically, phosphorus may be a coating additive/component in a matting agent. In some aspects, the matting agent includes titanium dioxide. Titanium dioxide may include a phosphorus-containing surface coating, such as manganese coated titanium dioxide. In some aspects, the phosphorus present in the polyamide composition is entirely supplied by additives, such as matting agents. In some aspects, the phosphorus present in the polyamide composition is supplied in part by an additive and in part as a phosphorus additive.

In some aspects, the phosphorus present in the polyamide formulation is supplied entirely by the matting agent, eg titanium dioxide additive, and no phosphorus, eg phosphorus additive, is separately added to the polyamide composition. For example, a titanium dioxide additive may be present in the polymer formulation, wherein the titanium dioxide comprises less than 2000 ppm phosphorus based on the total weight of the polyamide formulation. In some embodiments, the polyamide formulation may include a titanium dioxide additive and a phosphorus additive, which together provide less than 2000 ppm phosphorus based on the total weight of the polyamide formulation.

In some embodiments, inorganic pigment-like materials may be used as matting agents. The matting agent is titanium dioxide, barium sulfate, barium titanate, zinc titanate, magnesium titanate, calcium titanate, zinc oxide, zinc sulfide, lithopone, zirconium dioxide, calcium sulfate, barium sulfate, aluminum oxide, thorium oxide, magnesium oxide, silicon dioxide , talc, mica, and the like. Colored materials such as carbon black, copper phthalocyanine pigments, lead chromate, iron oxide, chromium oxide and ultramarine blue may also be used. In some aspects, matting agents include non-phenolic polynuclear compounds such as triphenyl benzene, diphenyl, substituted diphenyls, substituted naphthalenes, and chlorinated compounds of the aromatic and polynuclear type, such as chlorinated diphenyls. do.

The inventors have found that, in some cases, the use of a specific weight ratio of zinc to phosphorus minimizes the negative effects of phosphorus on polyamide formulations. For example, too much phosphorus in the polyamide composition can lead to polymer drip, increased polymer viscosity and inefficiencies in the production process.

In one embodiment, the weight ratio of zinc to phosphorus in the polyamide formulation is greater than 1.3:1, such as greater than 1.4:1, greater than 1.5:1, greater than 1.6:1, greater than 1.7:1, greater than 1.8:1 or 2:1 may be excessive. In terms of ranges, the weight ratio of zinc to phosphorus in the polyamide formulation is 1.3:1 to 30:1, such as 1.4:1 to 25:1, 1.5:1 to 20:1, 1.6:1 to 15:1, 1.8:1 to 10:1, 2:1 to 8:1, 3:1 to 7:1, or 4:1 to 6:1. In terms of upper limits, the weight ratio of zinc to phosphorus in the polyamide composition is less than 30:1, such as less than 28:1, less than 26:1, less than 24:1, less than 22:1, less than 20:1 or 15: may be less than 1. In some aspects, the polyamide formulation is free of phosphorus. In another aspect, very low amounts of phosphorus are present. In some cases, phosphorus is retained in the fibers/polymers along with zinc.

In one embodiment, the weight ratio of zinc to phosphorus in the polyamide formulation is less than 0.64:1, such as less than 0.62:1, less than 0.6:1, such as less than 0.5:1, less than 0.45:1, less than 0.4:1, It may be less than 0.3:1 or less than 0.25:1. In terms of ranges, the weight ratio of zinc to phosphorus in the polyamide formulation is from 0.001:1 to 0.64:1, such as 0.01:1 to 0.6:1, 0.05:1 to 0.5:1, 0.1:1 to 0.45:1, 0.2:1 to 0.4:1, 0.25:1 to 0.35:1 or 0.2:1 to 0.3:1. In terms of a lower limit, the weight ratio of zinc to phosphorus in the polyamide formulation is greater than 0.001:1, such as greater than 0.005:1, greater than 0.01:1, greater than 0.05:1, greater than 0.1:1, greater than 0.15:1 or 0.2: may be greater than 1.

In some cases, certain amounts of zinc and phosphorus are mixed into a polyamide formulation, such as a polyamide resin composition, in finely divided form, such as in the form of granules, flakes, etc., to produce fibers with substantially improved antibacterial activity. It has been determined that it is possible to provide a polyamide formulation which can subsequently be formed, eg extruded or otherwise drawn, into fibers by conventional methods for this purpose. Zinc and phosphorus are used in polyamide formulations in the amounts described above to provide fibers with permanent antibacterial activity.

As noted herein, by using a polyamide formulation having the foregoing zinc concentration, phosphorus concentration, and optionally relative viscosity range and/or other properties, the resulting antimicrobial fiber can retain a higher percentage of zinc. . The resulting nonwoven has (permanent or lasting) antibacterial properties.

In some embodiments, the antimicrobial fibers formed from the polyamide formulation have a zinc retention greater than 70%, such as greater than 75%, greater than 80%, greater than 90%, greater than 95%, or greater than 99% as measured by the dye bath test. have In terms of an upper limit, the antimicrobial fiber has a zinc retention of less than 100%, such as less than 99.9%, less than 98%, less than 95% or less than 90%. In terms of scope, the antimicrobial fiber has a zinc retention in the range of 70% to 100%, such as 75% to 99.9%, 80% to 99%, or 90% to 98%.

Zinc retention of fibers formed from polyamide formulations can be measured by the dye bath test according to the standard procedure below. The sample is cleaned through a scour process (all oil is removed). A scauer process may use a heated bath, for example performed at 71° C. for 15 minutes. A scouring solution comprising 0.25% large fiber weight ("owf") of Sterox (723 soap) non-ionic surfactant and 0.25% owf of TSP (trisodium phosphate) may be used. The sample was then rinsed with water, followed by cold water.

Cleaned samples can be tested according to chemical dye level procedures. This procedure results in a C.I. of 1.0% owf. A dye bath comprising Acid Blue 45, MSP (monosodium phosphate) at 4.0% owf and disodium phosphate or TSP at % owf sufficient to achieve a pH of 6.0 at a liquor to fiber ratio of 28:1 use the positioning in For example, if a pH of less than 6 is desired, a 10% solution of the desired acid may be added using an eye dropper until the desired pH is achieved. The dye bath can be preset so that the bath boils at 100°C. The sample is placed in the bath for 1.5 hours. For example, it may take about 30 minutes to reach boiling, then the bath is kept boiling for an hour. The sample is then removed from the bath and rinsed. The sample is then transferred to a centrifuge for water extraction. After water extraction, the samples were air dried. Then, measure and record ingredient amounts before and after the procedure.

In some embodiments, zinc may be provided as a zinc compound. The zinc compound may include zinc oxide, zinc acetate, zinc ammonium carbonate, zinc ammonium adipate, zinc stearate, zinc phenyl phosphinic acid, zinc pyrithione, and combinations thereof. In some aspects, zinc is provided in the form of zinc oxide. In some aspects, zinc is not provided via zinc phenyl phosphinate and/or zinc phenyl phosphonate. Advantageously, we have found that this particular zinc compound works particularly well because it readily dissociates to form more zinc ions.

In some embodiments, phosphorus may be provided as a phosphorus compound. In one aspect, the phosphorus compound is phenylphosphinic acid, diphenylphosphinic acid, sodium phenylphosphinate, phosphorous acid, benzene phosphonic acid, calcium phenylphosphinate, potassium B-pentylphosphinate, methylphosphinic acid, manganese hypophosphite, Sodium hypophosphite, monosodium phosphate, hypophosphorous acid, dimethylphosphinic acid, ethylphosphinic acid, diethylphosphinic acid, magnesium ethylphosphinic acid, triphenyl phosphite, diphenylmethyl phosphite, dimethylphenyl phosphite, ethyldiphenyl phosphite , phenylphosphonic acid, methylphosphonic acid, ethylphosphonic acid, potassium phenylphosphonate, sodium methylphosphonate, calcium ethylphosphonate, and combinations thereof. In some embodiments, the phosphorus compound may include phosphoric acid, benzene phosphinic acid, benzene phosphonic acid, and combinations thereof. Phosphorus or phosphorus compounds may also be dispersed into the polymer together with zinc.

In some embodiments, an antimicrobial agent, such as zinc, is added along with phosphorus to promote incorporation of the antimicrobial agent into the fibers/polymers of the polyamide composition. This procedure advantageously allows for a more uniform dispersion of the antimicrobial agent throughout the final fiber. Additionally, these combinations “embed” antimicrobial agents within the polyamide composition to help prevent or limit active antimicrobial ingredients from being washed out of the fibers.

In some embodiments, the polyamide composition may include additional antimicrobial agents other than zinc. The additional antimicrobial agent is any suitable antimicrobial agent, such as silver, copper and/or silver in metal form (eg particulate, alloys and oxides), salts (eg sulfate, nitrate, acetate, citrate and chloride) or ionic form. or gold. In some aspects, additional additives are added to the polyamide composition, such as additional antimicrobial agents.

antibacterial performance

In some embodiments, the formulation, structure and/or fiber exhibits improved antibacterial performance, for example after 24 hours. For example, the formulation, structure and/or fiber may contain at least 90%, such as at least 95%, at least 99%, at least 99.98%, at least 99.99%, at least 99.997%, at least 99.999% as measured by ISO 20743-13. or greater than or equal to 99.9999% Staphylococcus aureus reduction (growth inhibition).

In some embodiments, the formulations, structures and/or fibers exhibit improved antibacterial performance. For example, the formulation, structure and/or fiber may contain at least 90%, such as at least 95%, at least 99%, at least 99.98%, at least 99.99%, at least 99.999%, at least 99.9998% as measured by ISO 20743-13. or greater than or equal to 99.9999% or greater Klebsiella pneumoniae reduction (growth inhibition).

In terms of log reduction (S. aureus), the formulation, structure and/or fiber may exhibit a log reduction greater than 2.0, such as greater than 3.0, greater than 3.5, greater than 4.0, greater than 4.5, greater than 4.375 or greater than 5.0. .

In terms of log reduction (Klebsiella pneumoniae), the formulation, structure and/or fiber has a greater than 3.0, such as greater than 3.75, greater than 4.0, greater than 4.0, greater than 4.5, greater than 4.75, greater than 5.0, greater than 5.5 or log reduction greater than 6.0.

Fiber dimensions and distribution

Fibers disclosed herein are microfibers, such as fibers having an average fiber diameter of less than 25 microns, or nanofibers, such as fibers having an average fiber diameter of less than 1000 nm (1 micron).

In some embodiments, the fibers have an average fiber diameter that is less than the diameter of fibers formed for carpet-related applications that are not generally suitable for applications that touch the skin. For example, the fiber is less than 25 microns, such as less than 20 microns, less than 18 microns, less than 17 microns, less than 15 microns, less than 12 microns, less than 10 microns, less than 7 microns, less than 5 microns, less than 3 microns, or 2 microns. It may have an average fiber diameter of less than a micron.

In some cases, the average fiber diameter of the nanofibers in (the fibrous layer of) the nonwoven is less than 1 micron, such as less than 950 nanometers, less than 925 nanometers, less than 900 nanometers, less than 800 nanometers, less than 700 nanometers, 600 nanometers or less. It may be less than a nanometer or less than 500 nanometers. In terms of a lower limit, the average fiber diameter of the nanofibers can be at least 100 nanometers, at least 110 nanometers, at least 115 nanometers, at least 120 nanometers, at least 125 nanometers, at least 130 nanometers or at least 150 nanometers. In terms of range, the nanofibers have an average fiber diameter of 100 to 1000 nanometers, such as 110 to 950 nanometers, 115 to 925 nanometers, 120 to 900 nanometers, 125 to 800 nanometers, 125 to 700 nanometers, 130 to 600 nanometers or 150 to 500 nanometers. This average fiber diameter can distinguish nanofibers formed by the spinning method disclosed herein from nanofibers formed by the electrospinning method. Electrospinning methods typically have an average fiber diameter of less than 100 nanometers, for example less than 50 to 100 nanometers. Without being bound by theory, it is believed that these small nanofiber diameters can reduce the strength of the fibers and increase the difficulty in handling the nanofibers. Several electrospinning methods are contemplated.

In some cases, the average fiber diameter of the microfibers in the nonwoven may be less than 25 microns, such as less than 24 microns, less than 22 microns, less than 20 microns, less than 15 microns, less than 10 microns, or less than 5 microns. As a lower limit, the average fiber diameter of the microfibers in the nonwoven can be at least 1 micron, at least 2 microns, at least 3 microns, at least 5 microns, at least 7 microns, or at least 10 microns. In terms of range, the average fiber diameter of the nanofibers in the non-woven fibrous layer is 1 to 25 microns, such as 2 to 24 microns, 3 to 22 microns, 5 to 20 microns, 7 to 15 microns, 2 to 10 microns. or 1 to 5 microns. This average fiber diameter distinguishes microfibers formed by the spinning methods disclosed herein from fibers formed by electrospinning methods.

Use of the disclosed method and formulation results in a specific and beneficial distribution of fiber diameter. For example, in the case of nanofibers, less than 20% of the nanofibers may have a fiber diameter greater than 700 nanometers, such as less than 17.5%, less than 15%, less than 12.5% or less than 10%. In terms of the lower limit, at least 1%, such as at least 2%, at least 3%, at least 4% or at least 5% of the nanofibers may have a fiber diameter greater than 700 nanometers. In terms of range, 1 to 20%, such as 2 to 17.5%, 3 to 15%, 4 to 12.5%, or 5 to 10% of the nanofibers have a fiber diameter greater than 700 nanometers. These distributions can be compared to products formed by electrospinning (smaller average diameter (50-100 nanometers) and much narrower distribution) and products formed by non-nanofiber melt spinning (much larger distribution) can be distinguished. For example, non-nanofiber centrifugally spun nonwovens are disclosed in WO 2017/214085 and report fiber diameters of 2.08 to 4.4 microns with a very broad distribution shown in FIG. 10A of WO 2017/214085. However, electrospinning can still be used depending on the desired fiber diameter and distribution.

In the case of microfibers, the fiber diameter may preferably have a narrow distribution depending on the size of the microfibers. For example, less than 20% of the microfibers may have a fiber diameter greater than 2 microns above the average fiber diameter, such as less than 17.5%, less than 15%, less than 12.5%, or less than 10%. In terms of the lower limit, at least 1%, such as at least 2%, at least 3%, at least 4% or at least 5% of the microfibers have a fiber diameter greater than 2 microns above the average fiber diameter. In terms of range, 1 to 20% of the microfibers, such as 2 to 17.5%, 3 to 15%, 4 to 12.5%, or 5 to 10%, have a fiber diameter greater than 2 microns above the average fiber diameter. In a further example, the aforementioned distribution may be within 1.5 microns of the mean fiber diameter, such as within 1.25 microns, within 1 micron or within 500 nanometers.

In some embodiments, combinations of fibers having different average fiber diameters may be used. For example, a combination of nanofibers and microfibers may be used, such as a combination of fibers having an average fiber diameter of less than 1 micron and fibers having an average fiber diameter of 1 to 25 microns. In a further aspect, combinations of nanofibers with different average fiber diameters may be used. In another aspect, combinations of microfibers with different fiber diameters may be used. In another aspect, combinations of 3, 4, 5 or more fibers of different fiber diameters may be used.

In one embodiment, the benefits of having two related polymers with different RV values (both less than 330 and average fiber diameter less than 1 micron) blended for desired properties are envisaged. For example, the melting point of the polyamide may be increased, the RV adjusted, or other properties may be adjusted.

In one aspect, the benefits of having two related polymers with different RV values (both less than 330 and having average fiber diameters discussed herein) are envisaged for the desired properties. For example, the melting point of the polyamide may be increased, the RV adjusted, or other properties may be adjusted.

Antimicrobial fibers and fabrics advantageously have durable antimicrobial properties. In some aspects, antimicrobial fibers can be formed from polyamides, polyesters, and blends thereof. Antimicrobial fibers can be spun to form nonwovens that impart beneficial antibacterial properties to fabrics, for example apparel such as sportswear or other close-to-skin apparel.

In some embodiments, polyamide compositions are used to produce antimicrobial molded and engineered articles having permanent antimicrobial properties. In some aspects, molded and engineered articles comprising the antimicrobial polyamide composition are produced. In some aspects, the polyamide composition may further include additives such as, for example, EBS and polyethylene wax, two non-limiting examples of additives.

In some embodiments, the polyamide composition may be used in injection molding, extrusion molding, blowing or laminating treatment methods after direct addition during the molding process of plastics. In another aspect, a polyamide composition may be added to form a master batch used to form molded articles.

Some aspects relate to molded and processed articles comprising polyamide compositions. In some aspects, the molded and processed product is an industrial product, various wrapping paper, consumer product, or medical product, and the molded and processed product is an interior material such as blinds, wallpaper, and flooring; food-related products such as packaging films, storage containers and cutting boards; appliances such as humidifiers, washing machines and dishwashers; engineering materials such as water supply and drainage pipes and concrete; key materials in the medical field; and products for industrial purposes such as coatings. Molded and processed products are particularly useful as engineering materials, ie, medical devices/products for human implantation, such as medical catheters, prostheses, bone repair products, medical blood transfusion bags, and the like.

Antimicrobial fibers and fabrics advantageously have durable antimicrobial properties. In some aspects, the antimicrobial fibers may be formed from polyamides, polyesters, and blends thereof. The antimicrobial fibers can be spun to form nonwovens that impart beneficial antibacterial properties to textiles, for example apparel such as sportswear or skin contact apparel.

In some embodiments, the polyamide composition is used to produce antimicrobial molded and engineered articles having permanent antimicrobial properties. In some aspects, molded and engineered articles comprising the antimicrobial polyamide composition are produced. In some aspects, the polyamide composition may further include additives such as EBS and polyethylene wax, two non-limiting examples of additives.

In some embodiments, the polyamide composition may be added directly during the molding process of plastics and then used in injection molding, extrusion molding, blowing or laminating treatment methods. In another aspect, a polyamide composition may be added to form a master batch used to form molded articles.

Some aspects relate to molded and processed articles comprising polyamide compositions. In some aspects, the molded and processed products are industrial supplies, various wrappers, consumer products, or medical products, and the molded and processed products are interior materials such as blinds, wallpaper, and floor coverings; food-related products such as packaging films, storage containers, and cutting boards; appliances such as humidifiers, washing machines, and dishwashers; water supply and drainage pipes, and engineering materials such as concrete; core materials in the medical field; and industrial products such as coatings. Medical articles, that is, molded and processed products, are particularly useful for medical devices/products for insertion into the human body, such as medical catheters, prostheses, bone treatment products, and medical blood transfusion bags.

RV of polyamides, formulations, structures and fibers

The RV of polyamides and formulations (and resulting structures and products) is the ratio of solution or solvent viscosities, generally measured in a capillary viscometer at 25° C. (ASTM D 789) (2015). For the purposes of this invention, the solvent is formic acid containing 10% by weight of water and 90% by weight of formic acid. The solution is 8.4 wt % polymer dissolved in solvent.

RV(η _r ), as used in connection with the disclosed polymers and products, is the ratio of the absolute viscosity of the polymer solution to the absolute viscosity of formic acid:

η _r = (η _p /η _f ) = (f _r xd _p xt _p )/ η _f

In the above formula,

d _p =density of formic acid-polymer solution at 25 °C,

t _p = average efflux time for formic acid-polymer solution,

η _f = absolute viscosity of formic acid, kPa xs (E+6cP), and

f _r = viscometer tube factor, mm ² /s (cSt)/s = η _r /t ₃ .

A typical calculation for a 50 RV sample:

ηr = (fr x dp x tp)/ηf

In the above formula,

fr = viscometer tube factor, typically 0.485675 cSt/s;

dp = density of the polymer-formic acid solution, typically 1.1900 g/ml,

tp = average bleed time for polymer-formic acid solution, typically 135.00 seconds;

ηf = absolute viscosity of formic acid, typically 1.56 cP;

ηr = (0.485675 cSt/sx 1.1900 g/ml x 135.00 s)/ 1.56 cP = giving an RV of 50.0. The term t ₃ is the expulsion time of the S-3 calibration oil used in the measurement of the absolute viscosity of formic acid required by ASTM D789 (2015).

Advantageously, it has been found that the addition of zinc and optionally phosphorus in the proportions identified above can produce beneficial relative viscosities of polyamide formulations, structures and/or fibers. In some embodiments, RV is 1 to 100, for example 10 to 100, 20 to 100, 25 to 80, 30 to 60, 40 to 50, 1 to 40, 10 to 30, 15 to 20, 20 to 35, or 25 to 32 range. With respect to the lower limit, RV can be greater than 1, such as greater than 10, greater than 15, greater than 20, greater than 25, greater than 30, greater than 35, or greater than 40. In terms of an upper limit, the RV can be less than 100, such as less than 80, less than 60, less than 40, less than 35, less than 32, less than 30, or less than 20.

In some embodiments, the RV of the (precursor) polyamide has a lower limit of 2 or more, such as 3 or more, 4 or more, or 5 or more. In terms of the upper limit, polyamides have RV. 330 or less, 300 or less, 275 or less, 250 or less, 225 or less, 200 or less, 150 or less, 100 or less, or 60 or less. In terms of ranges, polyamides can range from 2 to 330, such as 2 to 300, 2 to 275, 2 to 250, 2 to 225, 2 to 200, 2 to 100, 2 to 60, 2 to 50, 2 to 40 , 10 to 40, or 15 to 40 and any value in between.

In some embodiments, the RV of the nonwoven structure has a lower limit of 2 or more, such as 3 or more, 4 or more, or 5 or more. With respect to the upper limit, the nanofibrous nonwoven product has an RV of 330 or less, 300 or less, 275 or less, 250 or less, 225 or less, 200 or less, 150 or less, 100 or less, or 60 or less. In terms of ranges, nonwovens may range from 2 to 330, such as 2 to 300, 2 to 275, 2 to 250, 2 to 225, 2 to 200, 2 to 100, 2 to 60, 2 to 50, 2 to 40, 10 to 40, or 15 to 40 and any value in between.

The relationship between the RV of the (precursor) polyamide composition and the RV of the nonwoven structure or fibers thereof may vary. In some aspects, the RV of the nonwoven may be lower than the RV of the polyamide composition. Reducing the RV has traditionally not been the preferred practice when spinning nylon 66. However, the inventors have found that there are advantages in the production of microfibers and nanofibers. It has been surprisingly found that the use of lower RV polyamide nylons, such as lower RV nylon 66, in the melt spinning process results in microfiber and nanofiber filaments with unexpectedly small filament diameters.

There are many different ways to lower RV. In some cases, the RV can be lowered by increasing the method temperature. However, in some embodiments, an increase in temperature may only slightly lower the RV because it affects the kinetics of the reaction and not the reaction equilibrium constant. The inventors have found that, advantageously, the RV of polyamides, such as nylon 66, can be lowered by depolymerizing the polymer with the addition of moisture. Before the polyamide begins to hydrolyze, it may contain up to 5% moisture, for example up to 4%, up to 3%, up to 2% or up to 1% moisture. This technology offers surprising advantages over conventional methods of adding other polymers, such as polypropylene, to polyamides (to reduce RV).

In some aspects, RV can be adjusted by lowering the temperature, adjusting the amount of zinc, and/or reducing moisture, for example. Again, temperature has a relatively moderate effect on RV tuning compared to moisture content. The moisture content may be reduced to as low as 1 ppm or higher, such as 5 ppm or higher, 10 ppm or higher, 100 ppm or higher, 500 ppm or higher, 1000 ppm or higher or 2500 ppm or higher. Reducing the moisture content is also beneficial for reducing the TDI and ODI values discussed further herein. Inclusion of a catalyst may affect the dynamics, but not the actual equilibrium constant.

In some aspects, the RV of the nonwoven is at least 20% less than the RV of the polyamide before spinning, such as at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, or at least 90% less.

In another aspect, the RV of the nonwoven is at least 5% greater than the RV of the polyamide before spinning, such as at least 10%, at least 15%, at least 20%, at least 25%, at least 30% or at least 35% greater.

In another aspect, the RV of the polyamide and the RV of the nonwoven may be substantially the same, for example within 5% of each other.

A further aspect of the present invention involves the preparation of an antimicrobial structure comprising polyamide nanofibers and/or microfibers having an average fiber diameter of less than 25 microns and an RV of 2 to 330. In this alternative embodiment, preferably the RV ranges include: 2 to 330, such as 2 to 300, 2 to 275, 2 to 250, 2 to 225, 2 to 200, 2 to 100, 2 to 60 , 2 to 50, 2 to 40, 10 to 40, or 15 to 40. The nanofibers and/or microfibers are subsequently converted into a nonwoven web. As the RV increases beyond about 10 to 30, for example 20 to 30, operating temperature becomes a larger parameter to consider. When the RV exceeds the range of about 10 to 30, for example 20 to 30, the temperature must be carefully controlled so that the polymer melts for processing purposes. A method or example of a melt technique, and a heating and cooling source that can be used in the machine to independently control the temperature of the fiber production equipment, is described in U.S. Patent No. 8,777,599 (herein incorporated by reference). Non-limiting examples include resistive heaters, radiant heaters, cold gas or heated gas (air or nitrogen), or conductive, convective or radiant heat transfer mechanisms.

Nonwoven Polyamide Properties

The spinning process described herein can form antimicrobial nonwoven polyamide structures (and fibers) with relatively low oxidative degradation index ("ODI") values. A lower ODI indicates less severe oxidative degradation during manufacturing. In some aspects, ODI can range from 10 to 150 ppm. ODI can be measured using gel permeation chromatography (GPC) with a fluorescence detector. The instrument is calibrated with an external standard of quinine. Dissolve 0.1 g of nylon in 10 mL of 90% formic acid. The solution is then analyzed by GPC with a fluorescence detector. The detector wavelength of ODI is 340 nm for excitation and 415 nm for emission. In terms of the upper limit, the ODI of the antimicrobial nonwoven polyamide may be 200 ppm or less, such as 180 ppm or less, 150 ppm or less, 125 ppm or less, 100 ppm or less, 75 ppm or less, 60 ppm or 50 ppm or less. In terms of the lower limit, the ODI of the antimicrobial nonwoven polyamide may be 1 ppm or more, 5 ppm or more, 10 ppm or more, 15 ppm or more, 20 ppm or more, or 25 ppm or more. In terms of range, the ODI of the antimicrobial nonwoven polyamide may be 1 to 200 ppm, 1 to 180 ppm, 1 to 150 ppm, 5 to 125 ppm, 10 to 100 ppm, 1 to 75 ppm, 5 to 60 ppm, or 5 to 50 ppm.

Additionally, the spinning process described herein can produce a relatively low thermal degradation index (“TDI”). A lower TDI indicates less severe thermal history of the polyamide during manufacture. The detector wavelengths for TDI are measured the same as for ODI except that they are 300 nm for excitation and 338 nm for emission. In terms of the upper limit, the TDI of the polyamide nanofiber nonwoven may be 4000 ppm or less, such as 3500 ppm or less, 3100 ppm or less, 2500 ppm or less, 2000 ppm or less, 1000 ppm or less, 750 ppm or 700 ppm or less. In terms of the lower limit, the TDI of the polyamide nanofiber nonwoven may be 20 ppm or greater, 100 ppm or greater, 125 ppm or greater, 150 ppm or greater, 175 ppm or greater, 200 ppm or greater, or 210 ppm or greater. In terms of range, the TDI of the polyamide nanofiber nonwoven is 20 to 400 ppm, 100 to 4000 ppm, 125 to 3500 ppm, 150 to 3100 ppm, 175 to 2500 ppm, 200 to 2000 ppm, 210 to 1000 ppm, 200 to 750 ppm, or 200 or Number of days 700 ppm there is.

TDI and ODI test methods are also disclosed in U.S. Patent No. 5,411,710. A lower TDI and/or ODI value is beneficial because it indicates that the antimicrobial nonwoven polyamide is more durable than products with higher TDI and/or ODI. As described above, TDI and ODI are measures of degradation, and products with large degradation are inferior in performance. For example, such products may have erratic dye uptake, low thermal stability, short life in filtration applications where the fibers are exposed to heat, pressure, oxygen or combinations thereof, and low toughness in industrial textile applications.

One possible method that can be used to form antimicrobial nonwoven polyamides with lower TDI and/or ODI is the inclusion of additives, particularly antioxidants, as described herein. These antioxidants are not required in conventional processes but can be used to inhibit degradation. Examples of useful antioxidants include copper halide and Nylostab® S-EED® available from Clariant.

The spinning methods described herein may also be used to produce a radiation of less than 600 CFM/ft ² , such as less than 590 CFM/ft ² , less than 580 CFM/ft ² , less than 570 CFM/ft ² , less than 560 CFM/ft ² or 550 CFM/ft 2 . It is possible to create an antimicrobial nonwoven polyamide structure (or fiber) with an air permeability value of less than ² . In terms of the lower limit, the antimicrobial nonwoven polyamide has an air permeability value of 50 CFM/ft ² or greater, 75 CFM/ft ^{2 or} greater, 100 CFM/ft ^{2 or} greater, 125 CFM/ft ^{2 or} greater, 150 CFM/ft 2 or greater, or 200 CFM/ft ² or greater. CFM/ft ² or higher. In terms of range, the antimicrobial nonwoven polyamide has 50 to 600 CFM/ft ² , 75 to 590 CFM/ft ² , 100 to 580 CFM/ft ² , 125 to 570 CFM/ft ² , 150 to 560 CFM/ft ² , or It may have an air permeability value of 200 to 550 CFM/ft ² .

The spinning methods described herein also have a filtration efficiency of 1 to 99.999%, such as 1 to 95%, 1 to 90%, 1.5 to 85%, or 2 to 80%, as measured by the TSI 3160 Automatic Filter Tester. Antibacterial non-woven polyamides can be produced. The TSI 3160 Automatic Filter Tester is used to test the efficiency of filter materials. Particle penetration and pressure drop are two important parameters measured using this instrument. Efficiency is 100% - penetration. A challenge solution of known particle size is used. The TSI 3160 is used to measure HEPA filters and uses DOP solutions. A combination of an electrostatic classifier and a double condensed particle counter (CPC) measures the majority penetrating particle size (MPPS) from 15 to 800 nm using monodisperse particles. Efficiency up to 99.999999% can also be tested.

formulation

In one embodiment, the formulation, structure and/or fiber comprises a matting agent comprising less than 3100 ppm zinc and at least a portion of the phosphorus and is capable of exhibiting a Staphylococcus aureus reduction of at least 95% as measured by ISO 20743-13. .

In one embodiment, the formulation, structure and/or fiber comprises 275 ppm to 3100 ppm zinc and little or no phosphorus, and nylon-6,6 as a polyamide may have an average fiber diameter of less than 1 micron; It can show a Staphylococcus aureus reduction of 95% or more, as measured by ISO 20743-13, and a Klebsiella pneumoniae reduction of 99% or more.

In one embodiment, the formulation, structure and/or fiber contains little or no zinc and phosphorus of less than 3100 ppm, and nylon-6,6 as a polyamide may have an average fiber diameter of less than 1 micron, ISO 20743 -13 can exhibit a Staphylococcus aureus reduction of 95% or greater, and a Klebsiella pneumoniae reduction of 99% or greater.

In one embodiment, the formulation, structure and/or fiber comprises 200 to 1500 ppm zinc (optionally provided as zinc oxide and/or zinc stearate) and little or no phosphorus, ranging from 10 to 30 can have an RV of less than 1 micron, can have an average fiber diameter of less than 1 micron, can exhibit a Staphylococcus aureus reduction of 99% or greater, as measured by ISO 20743-13, and a Klebsiella pneumoniae reduction of 99.9% or greater. can indicate

In another embodiment, the polymer comprises a nylon-based polymer, the zinc is provided via zinc oxide and/or zinc pyrithione, and the polyamide composition has a relative viscosity ranging from 10 to 100, such as from 20 to 100.

In another embodiment, the polymer comprises nylon-6,6, the zinc is provided via zinc oxide, the weight ratio of zinc to phosphorus is at least 2:1, and the polyamide composition has a weight ratio of 95 as measured by ISO 20743-13. % or greater Staphylococcus aureus reduction.

In one embodiment, the antimicrobial fiber comprises a polymer comprising less than 500 ppm zinc, and a matting agent comprising at least a portion of said phosphorus, wherein the antimicrobial fiber exhibits a Staphylococcus aureus reduction of at least 90%.

In another embodiment, the antimicrobial fiber comprises a polymer comprising nylon, wherein the zinc is provided in the form of zinc oxide and/or zinc pyrithione, and the polyamide composition has a relative viscosity ranging from 10 to 100, such as from 20 to 100. , the fibers have a zinc retention greater than 80% as measured by the dye bath test, and the average diameter of the fibers is less than 18 microns.

In another embodiment, the antimicrobial fiber comprises a polymer comprising nylon-6,6, the zinc is provided in the form of zinc oxide, the weight ratio of zinc to phosphorus is at least 2:1, and the fiber is exhibits a Staphylococcus aureus reduction of at least 95% as measured, the antimicrobial fibers have a zinc retention greater than 90% as measured by the dye bath test, and the antimicrobial fibers have an average diameter of less than 10 microns.

Method for forming fibers and non-woven structures

As described herein, the antimicrobial nonwoven polyamide structure is formed by spinning the formulation to form fibers arranged to form the structure.

In some embodiments, the present invention provides methods for imparting permanent antimicrobial properties to nonwoven fibers and structures and fabrics made from the polyamide formulations described herein. In some aspects, fibers, such as polyamide fibers, are made by spinning polyamide formed in a melt polymerization process. During the melt polymerization process of the polyamide composition, an aqueous monomer solution, for example a salt solution, is heated under controlled conditions of temperature, time and pressure to evaporate water and carry out polymerization of the monomers to produce a polymer melt. During the melt polymerization process, a sufficient amount of zinc and optionally phosphorus is used in the aqueous monomer solution to form the polyamide mixture prior to polymerization. Monomers are selected based on the desired polyamide composition. After zinc and phosphorus are present in the aqueous monomer solution, the polyamide composition can be polymerized. The polymerized polyamide can then be spun into fibers, for example by melt spinning, solution spinning, centrifugal spinning or electrospinning.

In some embodiments, a method of making antimicrobial fibers having permanent antimicrobial properties from a polyamide composition comprises preparing an aqueous monomer solution, less than 2000 ppm, for example less than 1500 ppm, less than 1000 ppm, less than 750 ppm, 500 ppm dispersed in the aqueous monomer solution. adding less than or less than 400 ppm zinc, adding less than 2000 ppm, such as less than 1500 ppm, less than 1000 ppm, less than 750 ppm, less than 500 ppm, or less than 400 ppm phosphorus, polymerizing the aqueous monomer solution to form a polymer melt, and spinning the polymer melt to form antimicrobial fibers. In this aspect, the polyamide composition includes the resultant aqueous monomer solution after zinc and phosphorus are added.

In some embodiments, the method includes preparing an aqueous monomer solution. The aqueous monomer solution may include amide monomers. In some embodiments, the concentration of the monomers in the aqueous monomer solution is less than 60%, e.g., less than 58%, less than 56.5%, less than 55%, less than 50%, less than 45%, less than 40%, less than 35% by weight or less than 30% by weight. In some embodiments, the concentration of the monomers in the aqueous monomer solution is greater than 20%, for example greater than 25%, greater than 30%, greater than 35%, greater than 40%, greater than 45%, greater than 50%, greater than 55 weight percent, or greater than 58 weight percent. In some embodiments, the concentration of the monomers in the aqueous monomer solution is 20 to 60% by weight, such as 25 to 58%, 30 to 56.5%, 35 to 55%, 40 to 50%, or 45 to 55% by weight. am. The remainder of the aqueous monomer solution may include water and/or additional additives. In some embodiments, monomers include amide monomers, including diacids and diamines, i.e., nylon salts.

In some embodiments, the aqueous monomer solution is a nylon salt solution. A nylon salt solution can be formed by mixing a diamine and a diacid with water. For example, water, diamine and dicarboxylic acid monomers are mixed to form a salt solution, for example adipic acid and hexamethylene diamine are mixed with water. In some embodiments, the diacid can be a dicarboxylic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, undecanoic acid dodecanedioic acid, maleic acid acid, glutaconic acid, traumatic acid, muconic acid, 1,2- or 1,3-cyclohexane dicarboxylic acid, 1,2- or 1,3-phenylenediacetic acid, 1,2- or 1,3-cyclohexane diacetic acid, isophthalic acid, terephthalic acid, 4,4'-oxybisbenzoic acid, 4,4-benzophenone dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, p-tert-butyl isophthalic acid and 2,5-furandicarboxylic acid and It may be selected from the group consisting of mixtures thereof. In some embodiments, the diamine is ethanol diamine, trimethylene diamine, putrescine, cadaverine, hexamethylene diamine, 2-methyl pentamethylene diamine, heptamethylene diamine, 2-methyl hexamethylene diamine, 3-methyl hexamethylene diamine, 2 ,2-dimethyl pentamethylene diamine, octamethylene diamine, 2,5-dimethyl hexamethylene diamine, nonamethylene diamine, 2,2,4- and 2,4,4-trimethyl hexamethylene diamine, decamethylene diamine, 5-methyl Nonane diamine, isophorone diamine, undecamethylene diamine, dodecamethylene diamine, 2,2,7,7-tetramethyl octamethylene diamine, bis(p-aminocyclohexyl)methane, bis(aminomethyl)norbornane, The group consisting of C ₂ -C ₁₆ aliphatic diamines optionally substituted with one or more C ₁ -C ₄ alkyl groups, aliphatic polyether diamines and furanic diamines such as 2,5-bis(aminomethyl)furan, and mixtures thereof. can be selected from. In a preferred embodiment, the diacid is adipic acid and the diamine is hexamethylene diamine, which are polymerized to form nylon-6,6.

It should be understood that the concept of producing polyamides from diamines and diacids also encompasses the concept of other suitable monomers such as amino acids or lactams. Without limiting the scope, examples of amino acids may include 6-aminohexanoic acid, 7-aminoheptanoic acid, 11-amino undecanoic acid, 12-aminododecanoic acid, or combinations thereof. Without limiting the scope of the present invention, examples of lactams may include caprolactam, enanthollactam, lauryllactam or combinations thereof. Suitable feeds for the disclosed process may include mixtures of diamines, diacids, amino acids and lactams.

After preparing the aqueous monomer solution, zinc is added to the aqueous monomer solution to form a polyamide composition. In some embodiments, less than 2,000 ppm zinc is dispersed in the aqueous monomer solution. In some aspects, additional additives, such as additional antimicrobial agents, are added to the aqueous monomer solution. Optionally, phosphorus is added to the aqueous monomer solution.

In some cases, the polyamide composition is polymerized using conventional melt polymerization processes. In one aspect, the aqueous monomer solution is heated under controlled conditions of time, temperature, and pressure to evaporate water, effect polymerization of the monomers, and provide a polymer melt. In some aspects, a specific weight ratio of zinc to phosphorus can advantageously promote the incorporation of zinc within a polymer, reduce thermal degradation of the polymer, and enhance its dyeability.

In some aspects, antimicrobial nylons are prepared by conventional melt polymerization of nylon salts. Typically, the nylon salt solution is heated under pressure (eg, 250 psig/1,825 x 10 ³ n/m ² ) to a temperature of, for example, about 245°C. The water vapor then increases the temperature, for example to about 270° C., while lowering the pressure to atmospheric pressure. Prior to polymerization, zinc and optionally phosphorus are added to the nylon salt solution. The resulting molten nylon is held at this temperature for a period of time to equilibrate before being extruded into fibers. In some aspects, the method can be performed as a batch or continuous process.

In some embodiments, during melt polymerization, zinc, for example zinc oxide, is added to the aqueous monomer solution. Antimicrobial fibers may include polyamides produced in a melt polymerization process other than a master batch process. In some aspects, the resulting fibers have permanent antibacterial properties. The resulting fibers can be used in applications such as hosiery, heavy hosiery and footwear, for example.

The antimicrobial agent can be added to the polyamide during melt polymerization, for example as a master batch or as a powder added to polyamide pellets, after which fibers can be formed from spinning. Then, the fibers are formed into a non-woven

In some aspects, the antimicrobial nonwoven structure is melt blown. Melt blowing is advantageously less expensive than electrospinning. Melt blowing is a type of process developed for forming microfibers and nonwoven webs. Until recently, microfibers were produced by melt blowing. Now, nanofibers may also be formed by melt blowing. Nanofibers are formed by extruding a molten thermoplastic polymer material or polyamide through a plurality of small holes. The resulting molten threads or filaments are passed into converging high velocity gas streams to attenuate or draw the filaments of molten polyamide to reduce their diameter. The meltblown nanofibers are then carried by a high velocity gas stream and deposited on a collecting surface or forming wire to form a nonwoven web of randomly dispersed meltblown nanofibers. The formation of nanofibers and nonwoven webs by meltblowing is well known in the art. See, for example, US Patents 3,704,198; 3,755,527; 3,849,241; 3,978,185; 4,100,324; and 4,663,220.

One option, "Island-in-the-sea," refers to fibers formed by extruding two or more polymer components from one spinning die, also referred to as conjugate spinning.

As is well known, electrospinning has many manufacturing parameters that can limit the spinning of certain materials. These parameters include: the charge of the spinning material and the spinning material solution; solution delivery (usually a stream of material expelled from a syringe); charge in the jet; electrical discharge of the fibrous membrane in the collector; External forces from the electric field on the spinning jet; density of the ejected jet; and the (high) voltage of the electrode and the shape of the collector. In contrast, the aforementioned nanofibers and products are advantageously formed without using an applied electric field as the primary spinning force, as is required in electrospinning processes. Thus, polyamides are not electrically charged and are not a component of the spinning process. Importantly, the dangerously high voltages required for electrospinning processes are not required for the presently disclosed process/product. In some embodiments, the process is a non-electrospinning process, and the resulting product is a non-electrospinning product produced via a non-electrospinning process.

An embodiment of making the nanofiber nonwovens of this invention is by two-phase spinning or meltblowing with a propellant gas through a spinning channel as generally described in U.S. Patent No. 8,668,854. The process involves a two-phase flow of a polymer or polymer solution and pressurized propellant gas (typically air) into thin, preferably converging channels. The channels are generally, preferably of an annular configuration. It is believed that the polymer is sheared by the gas flow inside a thin, preferably converging channel to create a polymer film layer on both sides of the channel. This polymeric film layer is further sheared into nanofibers by the propellant gas flow. Here, a moving collector belt can also be used, and the basis weight of the nanofiber nonwoven is controlled by adjusting the speed of the belt. The distance of the collector can also be used to control the fineness of the nanofibrous nonwoven. The process is better understood with reference to FIG. 1 .

Advantageously, the use of the foregoing polyamide precursors in a melt spinning process provides a significant advantage in production rate, e.g., at least 5%, at least 10%, at least 20%, at least 30%, at least 40% greater . An improvement can be observed as an improvement in area per hour compared to a conventional process, for example another process that does not use the features described herein. In some cases, the increase in production improves over a period of time. For example, during a given period of production, e.g., 1 hour, the disclosed process can reduce at least 5%, such as at least 10%, at least 20%, at least 30% or at least 40% over conventional processes or electrospinning processes. produce more products

1 is a process for spinning a nanofiber nonwoven comprising a polyamide supply assembly 110, an air supply 1210, a spinning cylinder 130, a collector belt 140 and a take up reel 150. Illustrates the schematic operation of the system. During operation, the polyamide melt or solution is supplied to the spinning cylinder 130 where it flows along with high pressure air through the thin channels of the cylinder and shears the polyamide into nanofibers. Details are found in the aforementioned U.S. Patent No. 8,668,854. The throughput rate and basis weight are controlled by the speed of the gear pump and the speed of the belt. Optionally, if necessary, functional additives such as charcoal, copper and the like may be added together with air supply.

In another configuration of the spinneret used in the system of FIG. 1, the particulate material may be added by a separate inlet as shown in US Pat. No. 8,808,594.

Another method that may be used is melt blowing the polyamide nanofiber webs disclosed herein (FIG. 2). Meltblowing involves extruding the polyamide at a relatively high rate, typically a hot gas flow. To prepare suitable nanofibers, see Hassan et al., J Membrane Sci., 427, 336-344, 2013 and Ellison et al., Polymer, 48 (11), 3306-3316, 2007, and, International Nonwoven Journal, Summer 2003, pg 21-28], the orifice and capillary geometry, and temperature must be carefully selected.

U.S. Patent No. 7,300,272 discloses fibers for extruding molten material to form a nanofiber array comprising a plurality of split distribution plates arranged in a stack such that each split distribution plate forms a layer within a fiber extrusion pack. Initiate the extrusion pack, and features in the split distribution plate form a distribution network that delivers molten material to the orifices of the fiber extrusion pack. Each split distribution plate includes a set of plate segments with gaps disposed between adjacent plate segments. Adjacent edges of the plate segments are shaped to form a reservoir along the gap, and a sealing plug is placed in the reservoir to prevent molten material from leaking out of the gap. The sealing plug may be formed by molten material leaking into the gap and collecting and solidifying in the reservoir or by placing the plug material in the reservoir in the pack assembly. This pack can be used to make nanofibers by the melt blowing system described in the aforementioned patent.

In one aspect, a method of making an antimicrobial nonwoven polyamide structure is disclosed. The method includes, for example, preparing an aqueous monomer solution to form a (precursor) polyamide (preparation of a monomer solution is well known). Zinc is added during preparation of the precursor (as discussed herein). In some cases, zinc is added and dispersed in the aqueous monomer solution.

Phosphorus may also be added. In some cases, the precursors are polymerized to form a polyamide composition. The method further includes spinning polyamide to form antimicrobial polyamide fibers and forming the antimicrobial polyamide fibers into an antimicrobial nonwoven structure. In some cases, the polyamide composition is melt spun, spinbonded, electrospun, solution spun or centrifugally spun.

Advantageously, spinning can be performed at low die pressures, which have been found to reduce or eliminate catastrophic fiber formation interruptions that create defects in the web structure. In some embodiments, the emission is less than 300 psig, for example less than 275 psig, less than 272 psig, less than 250 psig, less than 240 psig, less than 200 psig, less than 190 psig, less than 175 psig, less than 160 psig, or less than 155 psig. can be performed under die pressure. In terms of ranges, radiation can be from 10 psig to 300 psig, such as 25 psig to 275 psig, 35 psig to 272 psig, 50 psig to 250 psig, 75 psig to 240 psig, 75 psig to 200 psig, or 90 psig to It can be performed at die pressures in the range of 155 psig.

In some aspects, a method of making antimicrobial nonwoven fibers, optionally in the structures discussed above, is disclosed. The method includes preparing a formulation comprising a polyamide, zinc dispersed in the polyamide, and less than 2000 ppm phosphorus dispersed in the polyamide. The method includes spinning the formulation to form antimicrobial polyamide fibers having the composition and characteristics described herein. The method further includes forming the antimicrobial polyamide fibers into an antimicrobial nonwoven polyamide structure. Spinning is conducted at low die pressures as discussed above.

Fabrics can be made from non-woven fibers. Garments made from these fabrics can withstand normal abrasion and are free of any coatings, doping or topical treatments that tend to abrade off during knitting and weaving. The abrasion process causes dust on machines and fabrics and reduces the effective use time of the garment during normal wear and laundering.

polyamide

As described herein, antimicrobial polyamide compositions are used as polymers for nonwovens. As used herein, “polyamide composition” and like terms refer to compositions containing polyamides, including copolymers, terpolymers, polymer blends, alloys, and derivatives of polyamides. Further, "polyamide" as used herein means a polymer having as a component a polymer having a linkage between an amino group of one molecule and a carboxylic acid group of another molecule. In some aspects, polyamide is the component present in the greatest amount. For example, a polyamide containing 40 weight percent nylon 6, 30 weight percent polyethylene, and 30 weight percent polypropylene is referred to herein as a polyamide because the nylon 6 component is present in the greatest amount. In addition, since polyamide containing 20% by weight of nylon 6, 20% by weight of nylon 66, 30% by weight of polyethylene and 30% by weight of polypropylene is a component present in the maximum amount in combination with nylon 6 and nylon 66 components, this specification Also referred to as polyamide.

Exemplary polyamides and polyamide compositions are described in Kirk-Othmer, Encyclopedia of Chemical Technology, Vol. 18, p. 328-371 (Wiley 1982), the disclosures of which are incorporated herein by reference.

Briefly, polyamides are generally known as compounds containing repetitive amide groups as an integral part of the main polymer chain. Linear polyamides are of particular interest and can be formed from the condensation of difunctional monomers. Polyamide is often referred to as nylon. Although generally considered a condensation polymer, polyamides can also be formed by ring-opening polymerization. This manufacturing method is particularly important for some polymers where the monomer is a cyclic lactam, such as nylon 6. Certain polymers and copolymers and their preparation can be found in the following patents: U.S. Patents 4,760,129; 5,504,185; 5,543,495; 5,698,658; 6,011,134; 6,136,947; 6,169,162; 7,138,482; 7,381,788; and 8,759,475.

The use of polyamides in commercial applications has many advantages. Nylons are generally chemical and temperature resistant, giving them better performance than other polymers. It is also known to have improved strength, elongation and wear resistance compared to other polymers. Nylon is also very versatile and can be used in a variety of applications.

A particularly preferred class of polyamides for some applications is described in Glasscock et al., High Performance Polyamides Fulfill Demanding Requirements for Automotive Thermal Management Components, (DuPont), http://www2.dupont.com/Automotive/en_US/assets/downloads/ knowledg e%20center/HTN-whitepaper-R8.pdf available online June 10, 2016]. Such polyamides typically include one or more of the following structures.

Non-limiting examples of polymers included in polyamides include polyamides with combinations of other polymers such as polypropylene and copolymers, polyethylene and copolymers, polyesters, polystyrenes, polyurethanes, and combinations thereof. . Thermoplastic polymers and biodegradable polymers are also suitable for melt blowing or melt spinning into the nanofibers of the present invention. As discussed herein, the polymer may be melt spun or melt blown, with melt spinning or melt blowing by two-phase propellant-gas spinning being preferred (the polyamide composition as a liquid through a pressurized gas through a fiber-forming channel). including extrusion into shape). Other processes for forming the nonwoven structure may also be used, including spin bonding, solution spinning and centrifugal spinning.

The melting point of the nylon nanofiber products described herein, including copolymers and terpolymers, can be from 223°C to 390°C, such as from 223°C to 380°C, or from 225°C to 350°C. Additionally, the melting point can be greater than the typical nylon 66 melting point depending on any additional polymeric materials added.

Other polymeric materials that may be used in the antimicrobial nanofibrous nonwovens of the present invention include polyolefins, polyacetals, polyamides (as previously discussed), polyesters, cellulose ethers and esters, polyalkylene sulfides, polyarylene oxides, It includes both additive polymers and condensation polymer materials such as polysulfone, modified polysulfone polymers, and mixtures thereof. Preferred materials belonging to this general class include polyamides, polyethylene, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polypropylene, poly(vinylchloride), polymethyl Methacrylates (and other acrylic resins), polystyrene and copolymers thereof (including ABA type block copolymers), poly(vinylidene fluoride), poly(vinylidene chloride), varying degrees of hydrolysis (87% to 99.5%) cross-linked and non-cross-linked forms of polyvinyl alcohol. Additive polymers tend to be glassy (Tg above room temperature). This is the case with polyvinylchloride and polymethylmethacrylate, polystyrene polymer compositions or alloys, or with low crystallinity in the case of polyvinylidene fluoride and polyvinylalcohol materials. The nylon copolymers embodied herein can be prepared by combining various diamine compounds, various diacid compounds, and various cyclic lactam structures in a reaction mixture, and then forming a nylon with randomly positioned monomeric materials in a polyamide structure. . For example, a nylon 66-6,10 material is a nylon made from a C6 and C10 blend of hexamethylene diamine and diacid. Nylon 6-66-6,10 is a nylon made by copolymerizing epsilonaminocaproic acid, hexamethylene diamine, and a blend of C6 and C10 diacid materials.

In some embodiments, such as that described in U.S. Patent No. 5,913,993, a small amount of a polyethylene polymer can be blended with a nylon compound used to form a nanofibrous nonwoven having desirable characteristics. Adding polyethylene to nylon improves certain properties, such as softness. The use of polyethylene also lowers production costs and facilitates further downstream processing, such as bonding to other fabrics or to itself. Improved fabrics can be made by adding a small amount of polyethylene to the nylon feed material used to make nanofiber meltblown fabrics. More specifically, the fabric is formed by forming a blend of polyethylene and nylon 66, extruding the blend into a plurality of continuous filaments, directing the filaments through a die to meltblowing the filaments, and directing the filaments to a collecting surface to form a web. It can be prepared by depositing

Polyethylene useful in the process of this aspect of the invention may preferably have a melt index from about 5 g/10 min to about 200 g/10 min, such as from about 17 g/10 min to about 150 g/10 min. The polyethylene should preferably have a density of about 0.85 g/cc to about 1.1 g/cc, such as about 0.93 g/cc to about 0.95 g/cc. Most preferably, the polyethylene has a melt index of about 150 and a density of about 0.93.

The polyethylene used in the method of this aspect of the invention may be added at a concentration of about 0.05% to about 20%. In a preferred embodiment, the concentration of polyethylene will be from about 0.1% to about 1.2%. Most preferably, polyethylene is present at about 0.5%. The polyethylene concentration in fabrics produced according to the described method is approximately equal to the percentage of polyethylene added during the manufacturing process. Thus, the percentage of polyethylene in the fabric of this aspect of the invention will typically range from about 0.05% to about 20%, preferably about 0.5%. Thus, the fabric will typically comprise from about 80 to about 99.95 weight percent nylon. The filament extrusion step may be performed at about 250°C to about 325°C. Preferably, the temperature range is from about 280° C. to about 315° C., but may be lower if nylon 6 is used.

Blends or copolymers of polyethylene and nylon may be formed in any suitable manner. Typically, the nylon compound will be nylon 66, however, other polyamides of the nylon family may be used. Also, mixtures of nylons may be used. In one specific example, polyethylene is blended with a mixture of nylon 6 and nylon 66. Polyethylene and nylon polymers are typically supplied in the form of pellets, chips, flakes and the like. The desired amount of polyethylene pellets or chips may be blended with nylon pellets or chips in a suitable mixing device such as a rotary drum tumbler or the like, and the resulting blend may be introduced into the feed hopper of a conventional extruder or into a melt blown line. Blends or copolymers can also be produced by introducing suitable mixtures into a continuous polymerization spinning system.

Also, different species of a common polymer genus can be blended. For example, a high molecular weight styrenic material can be blended with a low molecular weight, high impact polystyrene. Nylon-6 materials include nylon-6; 66; It can be blended with nylon copolymers such as 6,10 copolymers. In addition, polyvinyl alcohol having a low hydrolysis degree, for example, 87% hydrolyzed polyvinyl alcohol may be blended with complete or superhydrolyzed polyvinyl alcohol having a hydrolysis degree of 98 to 99.9% or more. All of these mixed materials can be crosslinked using an appropriate crosslinking mechanism. Nylon can be crosslinked using a crosslinking agent that is reactive with the nitrogen atom at the amide linkages. Polyvinyl alcohol materials are formed using hydroxyl-reactive materials such as formaldehyde, urea, melamine-formaldehyde resins and their analogues, boric acid and other inorganic compounds, monoaldehydes such as dialdehydes, diacids, urethanes, epoxies and other known crosslinking agents. can be bridged. Crosslinking technology is a known and understood phenomenon in which crosslinking reagents react and form covalent bonds between polymer chains to substantially improve molecular weight, chemical resistance, overall strength and resistance to mechanical degradation.

One preferred mode is a polyamide comprising a first polymer that is conditioned or treated at an elevated temperature and a second polymer that is different (different polymer type, molecular weight or physical properties). Polymer blends can be reacted to form single chemical species. Preferred materials are chemically reacted into single polymeric species such that differential scanning calorimetry (DSC) analysis reveals a single polymeric material that provides enhanced stability when in contact with high temperatures, high humidity and challenging operating conditions. Preferred materials for use in the blended polymer system include nylon 6; nylon 66; nylon 6,10; nylon (6-66-6,10) copolymers and other generally aliphatic linear nylon compositions.

A suitable polyamide may include, for example, 20% nylon 6, 60% nylon 66 and 20% polyester by weight. Polyamides can include a combination of miscible polymers or a combination of immiscible polymers.

In some aspects, the polyamide can include nylon 6. As a lower limit, the polyamide can include nylon 6 in an amount of 0.1% by weight or greater, such as 1% by weight or greater, 5% by weight or greater, 10% by weight or greater, 15% by weight or greater, or 20% by weight or greater. there is. In terms of an upper limit, the polyamide may include nylon 6 in an amount of 99.9% or less, 99% or less, 95% or less, 90% or less, 85% or less, or 80% or less by weight. In terms of ranges, the polyamide is nylon in an amount of 0.1 to 99.9 weight percent, such as 1 to 99 weight percent, 5 to 95 weight percent, 10 to 90 weight percent, 15 to 85 weight percent, or 20 to 80 weight percent. 6 may be included.

In some aspects, the polyamide can include nylon 66. As a lower limit, the polyamide can include nylon 66 in an amount of 0.1% by weight or greater, such as 1% by weight or greater, 5% by weight or greater, 10% by weight or greater, 15% by weight or greater, or 20% by weight or greater. there is. In terms of an upper limit, the polyamide may include nylon 66 in an amount of 99.9% or less, 99% or less, 95% or less, 90% or less, 85% or less, or 80% or less by weight. In terms of ranges, the polyamide may be present in an amount of 0.1 to 99.9 wt%, such as 1 to 99 wt%, 5 to 95 wt%, 10 to 90 wt%, 15 wt% to 85 wt%, or 20 to 80 wt%. may include nylon 66.

In some aspects, the polyamide can include nylon 6I, where I stands for isophthalic acid. In terms of the lower limit, the polyamide may include nylon 6I in an amount of 0.1 wt% or more, such as 0.5 wt% or more, 1 wt% or more, 5 wt% or more, 7.5 wt% or more, or 10 wt% or more. . In terms of the upper limit, the polyamide may include nylon 6I in an amount of 50 wt% or less, 40 wt% or less, 35 wt% or less, 30 wt% or less, 25 wt% or less, or 20 wt% or less. In terms of ranges, the polyamide may be present in an amount of 0.1 to 50 wt%, such as 0.5 to 40 wt%, 1 to 35 wt%, 5 to 30 wt%, 7.5 to 25 wt%, or 10 to 20 wt%. Nylon 6I.

In some aspects, the polyamide can include nylon 6T, where T stands for terephthalic acid. In terms of the lower limit, the polyamide may include nylon 6T in an amount of 0.1% by weight or greater, such as 1% by weight or greater, 5% by weight or greater, 10% by weight or greater, 15% by weight or greater, or 20% by weight or greater. . In terms of an upper limit, the polyamide may include nylon 6T in an amount of 50 wt% or less, 47.5 wt% or less, 45 wt% or less, 42.5 wt% or less, 40 wt% or less, or 37.5 wt% or less. In terms of ranges, the polyamide may be present in an amount of 0.1 to 50 weight percent, such as 1 to 47.5 weight percent, 5 to 45 weight percent, 10 to 42.5 weight percent, 15 to 40 weight percent, or 20 to 37.5 weight percent. Nylon 6T.

Block copolymers are also useful in the process of the present invention. For these copolymers, the choice of solvent swelling agent is important. The chosen solvent makes both blocks soluble in the solvent. One example is ABA (styrene-EP-styrene) or AB (styrene-EP) polymers in methylene chloride solvent. If one component is not soluble in a solvent, it will form a gel. Examples of such block copolymers are styrene-b-butadiene and styrene-b-hydrogenated butadiene (ethylene propylene) of the Kraton® type, e-caprolactam-b-ethylene oxide of the Pebax® type , Sympatex® polyester-b-ethylene oxide, and polyurethanes of ethylene oxide and isocyanates.

addition polymers such as polyvinylidene fluoride, syndiotactic polystyrene, copolymers of vinylidene fluoride and hexafluoropropylene, polyvinyl alcohol, polyvinyl acetate, amorphous addition polymers such as poly(acrylonitrile) and acrylic acid; Copolymers thereof with methacrylates, polystyrene, poly(vinyl chloride) and various copolymers thereof, poly(methyl methacrylate) and various copolymers thereof are relatively easy to solution spin because they dissolve at low pressures and temperatures. is known to be It is contemplated that these can be melt spun according to the present invention as one method of making nanofibers.

There are practical advantages to forming a polymeric composition comprising two or more polymeric materials in the form of polymeric mixtures, alloys or cross-linked chemically bonded structures. We believe that these polymer compositions improve physical properties by altering polymer properties, such as improving polymer chain flexibility or chain mobility, increasing overall molecular weight, and providing reinforcement through network formation of the polymeric material. .

In one aspect of this concept, two related polymeric materials can be blended for beneficial properties. For example, high molecular weight polyvinylchloride may be blended with low molecular weight polyvinylchloride. Similarly, high molecular weight nylon materials can be blended with low molecular weight nylon materials.

Surprisingly, it has been found that these polyamides can provide odor control characteristics when used with the aforementioned zinc and/or phosphorus additives and formed into fabrics. In some cases, it has been found that conventional polymer resins using polyester polymer resins can retain and thrive on different types of bacteria compared to nylon. For example, micrococcus bacteria have been found to thrive on polyester-based fabrics. Accordingly, it has been found that the use of polyamide-based polymers, particularly nylon-based polymers, in combination with the aforementioned additives, surprisingly provides fabrics that exhibit significantly lower odor levels compared to similar fabrics using polyesters.

Example

Examples 1 to 6 and Comparative Examples A to E

A precursor polyamide composition was prepared using the ingredients listed in Table 1a below. For the zinc oxide samples, a zinc oxide masterbatch of nylon 6 was mixed with nylon 6,6 flakes to achieve the desired zinc amount. For the zinc stearate samples, zinc stearate was added as a powder to nylon 6,6 flakes and processed through a twin screw extruder to achieve the desired amount of zinc, dispensing the material through the polymer. For the copper acetate samples, copper acetate was added to the salt solution to achieve the copper amount.

[Table 1a]

Using a conventional meltblowing system, the precursor composition was blown into fibers. The fibers were placed in a scrim placed on a moving belt. A nonwoven web was thus formed. For this process, an extruder with a high compression screw was used. The (precursor) polyamide die temperature was about 323° C. and air was used as the gas.

As mentioned above, fibers were spun onto the scrim, which was used to add integrity to the (nano)fiber web of the present invention. The polyamides had RVs (before spinning) listed in Table 1.

The web was tested for antibacterial efficacy (according to ISO20743-13:2013). The results are shown in Table 1b.

[Table 1b]

As shown in Table 1a, webs comprising the disclosed amounts of zinc exhibit surprisingly high reductions (after 24 hours) of both Staphylococcus aureus and Klebsiella pneumoniae, eg greater than 99.97% in all cases. showed a decrease. In contrast, Comparative Examples A to E, which used little or no zinc compound (or elemental zinc), showed less than 95% of Staphylococcus aureus, less than 98.9% of Klebsiella pneumoniae, and less than 80% in most cases of Staphylococcus aureus. showed a decrease in

In particular, the web exhibited a particularly good reduction of Klebsiella pneumoniae compared to Comparative Examples A-D, eg at least a 99.999% reduction (98.8% for Comparative Example C, Comparative Examples A, B and Comparative Examples). less than 50% for D). Importantly, the disclosed webs performed better than other metals, such as copper in Comparative Example E (99.999+ for Examples 1-6 vs. only 31.0% for Comparative Example E).

Log reduction numbers are often used in industry as a measure of efficacy because they emphasize differentiation at the upper limit of percent reduction, eg, percent reduction greater than 99.9%.

In terms of microbial growth, the log reduction tells you how effective your product is. The greater the log reduction, the more effective the product is in controlling microbial growth. In some instances, during product efficacy testing, the number of colony forming units (CFU) is counted at the beginning of the test. The reduction is measured over a predetermined period of time (eg 24 hours). The result of the difference between control and test product is then presented as a log reduction.

As shown in Table lb, for Klebsiella pneumoniae, the disclosed webs exhibited log reductions well above 2, for example greater than 4.5, in most cases. In contrast, Comparative Examples A-E, including Comparative Example E, which used a copper compound as the antimicrobial agent, had a log reduction of less than 2, eg less than 1.0 in most cases.

The performance of Staphylococcus aureus was also unexpectedly good. The web showed at least 99.98% Staphylococcus aureus reduction compared to Comparative Examples A-D (only 94.5% for Comparative E and less than 80% for Comparative Examples A-D). Importantly, the disclosed web exhibited superior performance compared to other metals, such as copper of Comparative Example E (99.98+ for Examples 1-6 vs. only 94.5% for Comparative Example E).

In addition, the disclosed webs show log reductions well above 2, eg greater than 3.5 in most cases. In contrast, Comparative Examples A-E, including Comparative Example E, which used a copper compound as the antimicrobial agent, showed a log reduction of less than 1.5, eg less than 1.0 in most cases.

These examples and comparative examples show the criticality of the disclosed zinc compounds (optionally in disclosed amounts) versus other antimicrobial agents and control samples.

Examples 7 and 8 and Comparative Examples F and G

A nonwoven web was made using the process described above, using zinc oxide added as a master batch. The characteristics and performance characteristics of several specific samples are shown in Table 2a.

[Table 2a]

Comparative Examples F and G were prepared similarly but without the zinc compound.

The web was tested for antibacterial efficacy (according to ISO20743-13:2013). The results are shown in Table 2b.

[Table 2b]

As shown in Table 2b, webs comprising the disclosed amounts of zinc (Examples 7 and 9) exhibit surprisingly high reductions (after 24 hours) of both Staphylococcus aureus and Klebsiella pneumoniae, e.g. in all cases showed a reduction of more than 99.990% in In contrast, Comparative Examples F and G, which did not use a zinc compound (or elemental zinc), showed a reduction of less than 50% for Staphylococcus aureus and less than 99.99% for Klebsiella pneumoniae.

In particular, the web showed a particularly good reduction of Klebsiella pneumoniae compared to Comparative Examples F and G, eg at least 99.9999% (only 99.9802% for Comparative Example F and 99.7467 for Comparative Example G) reduction. .

As shown in Table 2b, for Klebsiella pneumoniae, the disclosed webs exhibited log reductions well above 3.7, such as greater than 4 or greater than 5. In contrast, Comparative Examples F and G exhibited log reductions of less than 4.

The performance of Staphylococcus aureus was also unexpectedly good. Web showed a Staphylococcus aureus reduction of over 99.990% compared to Comparative Examples F and G (only 43.68% for Comparative F and less than 25% for Comparative G).

In addition, the disclosed web exhibited a log reduction greater than 3.5, for example greater than 4. In contrast, Comparative Examples F and G exhibit log reductions of less than 1.5, eg less than 1.0 in most cases.

Examples 1 to 4 and 6 and Comparative Examples A and C (die pressure reduction)

In addition to antibacterial benefits, the use of zinc in the disclosed amounts has been shown to unexpectedly contribute to process efficiencies such as, for example, die pressure reduction and/or RV improvement.

The precursor polyamide compositions of Examples 1 to 4 and 6 and Comparative Examples A and C were melt blown into webs as described above. The die pressures used are listed in Table 3. The rest of the process parameters were kept essentially constant, and sample A had a slightly higher throughput.

[Table 3]

As shown, use of the disclosed composition allowed for a significant reduction in die pressure and/or RV, eg less than 272 psig (to achieve a web having the same or similar properties). Die pressure may contribute to the elimination or reduction of fiber formation disruptions. In some cases, die pressures higher than 272 psig have been found to allow more fiber formation disruptions, which can be detrimental to many properties such as filtration efficiency and water repellent performance. As shown, Comparative Examples A and C were produced at higher die pressures (eg, 272 psig and 605 psig). Thus, webs with the same or similar characteristics are achieved using these higher die pressures. And higher die pressures are known to contribute to other defects (eg fiber breaks). Using the disclosed compositions with zinc content allows the process to achieve lower die pressures at higher throughputs, increasing the production rate and productivity of the process.

Examples 10, 11 and Comparative Examples H to M (die pressure reduction)

Precursor polyamide compositions of Examples 10 and 11 and Comparative Examples H to M were prepared as shown in Table 4. Examples 10 and 11 were prepared using the process described above using zinc stearate as the zinc compound. Comparative Examples H-M were prepared similarly but without the zinc compound.

This precursor polyamide composition was melt blown into a web as described above. The die pressures used are also shown in Table 4. The remaining process parameters were kept essentially constant.

[Table 4]

As noted above, use of the disclosed formulations allowed for a significant reduction in die pressure, eg less than 260 psig (to achieve a web having the same or similar properties). Comparative Examples H-M were prepared at higher die pressures, e.g., at least 260 psig and in most cases well above 350 psig. Therefore, webs with the same or similar properties were achieved using these higher die pressures.

mode

The following aspects are contemplated. All combinations of features and aspects are contemplated.

Aspect 1:

non-woven polyamides having an average fiber diameter of less than 25 microns; less than 2000 ppm zinc dispersed in the polyamide; and less than 2000 ppm phosphorus

wherein the weight ratio of zinc to phosphorus is at least 1.3:1, or less than 0.64:1.

Aspect 2: An aspect of aspect 1, wherein the weight ratio of zinc to phosphorus is at least 2:1.

Aspect 3: An aspect of aspect 1 or 2, wherein the relative viscosity of the polyamide composition ranges from 10 to 100, such as from 20 to 100.

Aspect 4: The aspect of any one of aspects 1-3, wherein the polyamide composition comprises less than 500 ppm zinc.

Aspect 5: The aspect of any one of aspects 1-4, wherein the polyamide composition comprises a matting agent comprising at least a portion of said phosphorus.

Aspect 6: In an aspect of any one of aspects 1-5, the polyamide composition is free of phosphorus.

Aspect 7: The aspect of any one of aspects 1-6, wherein the zinc is zinc oxide, zinc acetate, zinc ammonium carbonate, zinc ammonium adipate, zinc stearate, zinc phenylphosphinic acid, zinc pyrithione, and/or combinations thereof. It is provided through a zinc compound containing.

Aspect 8: In an aspect of aspect 7, the zinc compound is not zinc phenyl phosphinate and/or zinc phenyl phosphonate.

Aspect 9: The method of any one of Aspects 1-8, wherein the phosphorus is phosphorus acid, benzene phosphinic acid, benzene phosphonic acid, manganese hypophosphite, sodium hypophosphite, monosodium phosphate, hypophosphorous acid, phosphorous acid, and/or combinations thereof. It is provided through a phosphorus compound containing.

Aspect 10: The embodiment of any one of Aspects 1-9, wherein the polyamide composition comprises less than 500 ppm zinc, the polymeric resin composition comprises a matting agent comprising at least a portion of said phosphorus, wherein the polymer comprises an ISO Inhibits the growth of Staphylococcus aureus by more than 90% as measured by 20743-13.

Aspect 11: The aspect of any one of aspects 1-10, wherein the polyamide comprises nylon, the zinc is provided via zinc oxide and/or zinc pyrithione, and the polyamide composition has a relative viscosity of 10 to 100, such as ranges from 20 to 100.

Example 12: The aspect of any one of aspects 1-11, wherein the polyamide comprises nylon-6,6, wherein the zinc is provided via zinc oxide, and the weight ratio of zinc to phosphorus is at least 2:1; The polyamide composition inhibits the growth of Staphylococcus aureus by more than 95% as measured by ISO 20743-13.

Aspect 13: The aspect of any one of Aspects 1-12, further comprising one or more additional antimicrobial agents comprising silver, tin, copper and gold, and alloys, oxides and/or combinations thereof.

Aspect 14: The aspect of any one of aspects 1-13, wherein the nonwoven has a melting point greater than 225°C.

Aspect 15: The aspect of any one of aspects 1-14, wherein the nonwoven polyamide is melt spun, spinbonded, electrospun, solution spun or centrifugally spun.

Aspect 16: The aspect of any one of aspects 1-15, wherein the nonwoven polyamide has an average fiber diameter of 1000 nanometers or less.

Aspect 17: The aspect of aspect 16, wherein no more than 20% of the fibers have a diameter greater than 700 nanometers.

Aspect 18: The aspect of any one of aspects 1-17, wherein the polyamide comprises nylon 66 or nylon 6/66.

Aspect 19: The aspect of any one of aspects 1-18, wherein the polyamide comprises a high temperature nylon.

Aspect 20: The aspect of any one of aspects 1-19, wherein the polyamide is N6, N66, N6T/66, N612, N6/66, N6I/66, N66/6I/6T, N11, and/or N12. Including, where "N" means nylon.

Aspect 21: The aspect of any one of aspects 1-20, wherein the nonwoven polyamide has an air permeability value of less than 600 CFM/ft ² .

Aspect 22: The aspect of any one of aspects 1-21, wherein the nonwoven polyamide has a basis weight of 200 GSM or less.

Aspect 23: a nonwoven polyamide having an average fiber diameter of less than 25 microns; less than 2000 ppm zinc dispersed in the polymer; and less than 2000 ppm phosphorus.

Aspect 24: The aspect of aspect 23, wherein the weight ratio of zinc to phosphorus is at least 1.3:1, or less than 0.64:1.

Aspect 25: The aspect of any one of aspects 23 or 24, wherein the weight ratio of zinc to phosphorus is at least 2:1.

Aspect 26: The aspect of any one of aspects 23-25, wherein the fibers have an average diameter of less than 20 microns.

Aspect 27: The aspect of any one of aspects 23-26, wherein the polymer comprises less than 2000 ppm zinc.

Aspect 28: The aspect of any one of aspects 23-27, wherein the polymer comprises a matting agent comprising at least a portion of said phosphorus.

Aspect 29: The aspect of any one of Aspects 23-28, wherein the antimicrobial fiber has a zinc retention greater than 70% as measured by the Dye Bath Test.

Embodiment 30: The embodiment of any one of embodiments 23-29, wherein the zinc is zinc oxide, zinc acetate, zinc ammonium carbonate, zinc ammonium adipate, zinc stearate, zinc phenyl phosphinic acid, zinc pyrithione and/or any of these it is a combination

Embodiment 31: The embodiment of any one of embodiments 23-30, wherein the phosphorus is selected from phosphoric acid, benzene phosphinic acid, benzene phosphonic acid, manganese hypophosphite, sodium hypophosphite, monosodium phosphate, hypophosphorous acid, phosphorous acid, and/or any of these It is a phosphorus compound containing a combination.

Aspect 32: The aspect of any one of Aspects 23-31, wherein the polyamide comprises less than 500 ppm zinc, the polymer comprises a matting agent comprising at least a portion of said phosphorus, and the antimicrobial fiber complies with ISO 20743-13. inhibits the growth of Staphylococcus aureus by more than 90% as measured by

Aspect 33: The aspect of any one of aspects 23-32, wherein the polyamide comprises nylon, the zinc is provided in the form of zinc oxide and/or zinc pyrithione, and the polymeric resin composition has a relative viscosity of from 10 to 100 , eg, in the range of 20 to 100, the antimicrobial fibers have a zinc retention greater than 80% as measured by the dye bath test, and the fibers have an average diameter of less than 18 microns.

Embodiment 34: The embodiment of any one of embodiments 23-33, wherein the polyamide comprises nylon-6,6, the zinc is provided in the form of zinc oxide, the weight ratio of zinc to phosphorus is at least 2:1, and the antibacterial The fibers inhibit the growth of Staphylococcus aureus by more than 95% as measured by ISO 20743-13, the antimicrobial fibers have a zinc retention greater than 90% as measured by the dye bath test, and the antimicrobial fibers have an average diameter of 10 microns is less than

Aspect 35: The aspect of any one of Aspects 23-34, wherein the polymer further comprises one or more additional antimicrobial agents comprising silver, tin, copper and gold, and alloys, oxides and/or combinations thereof.

Aspect 36: The aspect of any one of aspects 23-35, wherein the nonwoven has a melting point of at least 225°C.

Aspect 37: The aspect of any one of aspects 23-36, wherein the nonwoven polyamide is melt spun, spinbonded, electrospun, solution spun or centrifugally spun.

Aspect 38: The aspect of any one of aspects 23-37, wherein the nonwoven polyamide has an average fiber diameter of 1000 nanometers or less.

Aspect 39: The aspect of aspect 38, wherein no more than 20% of the fibers have a diameter greater than 700 nanometers.

Aspect 40: The aspect of any one of aspects 23-39, wherein the polyamide comprises nylon 66 or nylon 6/66.

Aspect 41: The aspect of any one of aspects 23-40, wherein the polyamide comprises high temperature nylon.

Aspect 42: The aspect of any one of aspects 23-41, wherein the polyamide is N6, N66, N6T/66, N612, N6/66, N6I/66, N66/6I/6T, N11, and/or N12. Including, where "N" means nylon.

Aspect 43: The aspect of any one of aspects 23-42, wherein the nonwoven polyamide has an air permeability value of less than 600 CFM/ft ² .

Aspect 44: The aspect of any one of aspects 23-43, wherein the nonwoven polyamide has a basis weight of 200 GSM or less.

Embodiment 45: A method of making an antimicrobial nonwoven polyamide having permanent antibacterial properties, the method comprising:

preparing an aqueous solution of monomers forming polyamide; adding less than 2000 ppm of zinc dispersed in the aqueous monomer solution; adding less than 2000 ppm of phosphorus; polymerizing the aqueous monomer solution to form a polyamide; spinning the polyamide to form antimicrobial polyamide fibers; and forming the antimicrobial polyamide fibers into an antimicrobial non-woven polyamide having a fiber diameter of less than 25 microns.

wherein the weight ratio of zinc to phosphorus is at least 1.3:1, or less than 0.64:1.

Embodiment 46: The method of embodiment 45, wherein the polymer comprises less than 2000 ppm zinc.

Aspect 47: The aspect of any one of aspects 45 or 46, wherein the antimicrobial fiber has a zinc retention greater than 70% as measured by the dye bath test.

Aspect 48: The aspect of any one of Aspects 45-47, wherein adding phosphorus comprises adding a matting agent comprising at least a portion of the phosphorus.

Aspect 49: The aspect of any one of aspects 45-48, wherein the polyamide is melt spun by meltblowing with a high velocity gas stream through a die.

Aspect 50: The aspect of any one of aspects 45-49, wherein the polyamide is applied to two-phase propellant-gas spinning comprising extruding the polyamide composition in liquid form with a pressurized gas through a fiber-forming channel. melt-spun by

Aspect 51: The aspect of any one of aspects 45-50, wherein the nonwoven is formed by collecting the fibers on a moving belt.

Aspect 52: The aspect of any one of aspects 45-51, wherein the relative viscosity of the polyamide in the nonwoven is reduced compared to the polyamide prior to spinning and forming the nonwoven.

Aspect 53: The aspect of any one of aspects 45-52, wherein the relative viscosity of the polyamide in the nonwoven is the same or increased compared to the polyamide prior to spinning and forming the nonwoven.

Aspect 54: The aspect of any one of aspects 45-53, wherein the nonwoven comprises a nylon 66 polyamide melt spun and formed into the nonwoven, wherein the nonwoven has a TDI of at least 20 ppm and an ODI of at least 1 ppm. .

Aspect 55: The aspect of any one of aspects 45-54, wherein the nonwoven comprises a nylon 66 polyamide melt spun into fibers and formed into the nonwoven, wherein no more than 20% of the fibers have a diameter greater than 25 microns. .

Aspect 56: The aspect of any one of aspects 45-49, wherein the polyamide is melt spun, spinbonded, electrospun, solution spun or centrifugally spun.

Aspect 57: less than 4000 ppm zinc dispersed in non-woven polyamide fibers; and less than 2000 ppm phosphorus, wherein the fibers have an average fiber diameter of less than 25 microns; The polyamide structure exhibits Staphylococcus aureus reduction of greater than 90% as measured by ISO 20743-13.

Aspect 58: The aspect of aspect 57, wherein the weight ratio of zinc to phosphorus is at least 1.3:1, or less than 0.64:1.

Aspect 59: An aspect of aspect 57 or 58, wherein the polyamide composition has a relative viscosity of less than 100.

Embodiment 60: The embodiment of any one of embodiments 57-59, wherein the polyamide composition comprises less than 3100 ppm zinc, the polyamide composition comprises a matting agent comprising at least a portion of said phosphorus, and wherein the polyamide complies with ISO 20743 -13 indicates a Staphylococcus aureus reduction of greater than 90% as measured by

Aspect 61: The aspect of any one of aspects 57-60, wherein the nonwoven polyamide is melt spun, spinbonded, electrospun, solution spun, or centrifugally spun.

Aspect 62: The aspect of any one of aspects 57-61, wherein no more than 20% of the fibers have a diameter greater than 700 nanometers.

Aspect 63: The aspect of any one of aspects 57-62, wherein the polyamide comprises nylon 66 or nylon 6/66.

Aspect 64: less than 4000 ppm zinc dispersed in non-woven polyamide fibers; and less than 2000 ppm phosphorus, wherein the fiber has an average fiber diameter of less than 25 microns, wherein the polyamide structure has a Staphylococcus aureus reduction of at least 90% as measured by ISO 20743-13. indicates

Aspect 65: The aspect of aspect 64, wherein the weight ratio of zinc to phosphorus is at least 1.3:1; or less than 0.64:1.

Aspect 66: The aspect of aspect 64 or 65, wherein the fibers have an average diameter of less than 20 microns.

Aspect 67: The aspect of any one of Aspects 64-66, wherein the nonwoven polyamide comprises less than 3100 ppm zinc.

Aspect 68: The aspect of any one of aspects 64-67, wherein the antimicrobial fiber has a zinc retention greater than 70% as measured by the dye bath test.

Aspect 69: The aspect of any one of Aspects 64-68, wherein the nonwoven polyamide comprises less than 3200 ppm zinc, the polymer comprises a matting agent comprising at least a portion of said phosphorus, and the antimicrobial fiber is ISO 20743-13 represents a Staphylococcus aureus reduction of greater than 90% as measured by

Aspect 70: The aspect of any one of aspects 64-69, wherein the nonwoven polyamide is melt spun, spinbonded, electrospun, solution spun, or centrifugally spun.

Aspect 71: The aspect of any one of aspects 64-69, wherein the polyamide comprises nylon 66 or nylon 6/66.

Aspect 72: A method of making an antimicrobial nonwoven polyamide structure having permanent antibacterial properties, the method comprising:

preparing a precursor polyamide optionally comprising an aqueous monomer solution;

dispersing less than 4000 ppm zinc within the precursor polyamide;

dispersing less than 2000 ppm phosphorus within the precursor polyamide;

polymerizing the precursor polyamide to form a polyamide composition;

spinning the polyamide composition to form antimicrobial polyamide fibers; and

Forming the antimicrobial polyamide fibers into an antimicrobial nonwoven structure having a fiber diameter of less than 25 microns.

includes

Embodiment 73: The embodiment of embodiment 72, wherein the antimicrobial nonwoven polyamide has a zinc retention greater than 70% as measured by the dye bath test.

Aspect 74: The aspect of aspect 72 or 73, wherein the weight ratio of zinc to phosphorus is at least 1.3:1, or less than 0.64:1.

Aspect 75: The aspect of any one of aspects 72-74, wherein the polyamide is melt spun by meltblowing with a high velocity gas stream through a die.

Aspect 76: The aspect of any one of aspects 72-75, wherein the nonwoven comprises a nylon 66 polyamide melt spun into fibers and formed into the nonwoven, wherein no more than 20% of the fibers have a diameter greater than 25 microns. .

Aspect 77: The aspect of any one of aspects 72-76, wherein the polyamide is melt spun, spinbonded, electrospun, solution spun or centrifugally spun.

Embodiment 78: A non-woven polyamide structure having antimicrobial properties, comprising non-woven polyamide fibers having an average fiber diameter of less than 25 microns, wherein less than 4000 ppm zinc is dispersed therein, wherein the polyamide composition is characterized by ISO 20743-13 A non-woven polyamide structure that, as measured, exhibits a Staphylococcus aureus reduction of greater than 90%.

Embodiment 79: A method of making an antimicrobial nonwoven polyamide structure having antimicrobial properties, the method comprising:

preparing a formulation comprising a polyamide, less than 4000 ppm zinc dispersed in the polyamide, and less than 2000 ppm phosphorus dispersed in the polyamide;

spinning the formulation to form antimicrobial polyamide fibers having a fiber diameter of less than 25 microns; and

Forming the antimicrobial polyamide fibers into an antimicrobial non-woven polyamide structure

including, where

wherein the fiber is spun using a die pressure of less than 275 psig.

Although the invention has been described in detail, modifications within the spirit and scope of the invention will be readily apparent to those skilled in the art. In view of the foregoing discussion, pertinent technical knowledge, and references cited above in connection with background and detailed description, the disclosures of these are all hereby incorporated by reference. It is also to be understood that aspects of the invention, and some of the various aspects and various features recited in the appended claims below, may be combined or interchanged, in whole or in part. In the foregoing description of various aspects, those aspects with reference to another aspect may be appropriately combined with other aspects as will be understood by those skilled in the art.

Claims (23)

100 ppb to 4000 ppm zinc dispersed in nonwoven polyamide fibers; and
0 ppm to 2000 ppm phosphorus
Non-woven polyamide fibers containing
A non-woven polyamide structure having antimicrobial properties, including
the fibers have an average fiber diameter of less than 25 microns;
no more than 20% of the fibers have a diameter greater than 2 microns;
The non-woven polyamide structure, wherein the polyamide structure exhibits a Staphylococcus Aureus reduction of 90% or more as measured by ISO 20743-13. According to claim 1,
A nonwoven polyamide structure having a weight ratio of zinc to phosphorus of at least 1.3:1, or less than 0.64:1. According to claim 1,
A nonwoven polyamide structure wherein the relative viscosity of the polyamide composition is less than 100. According to claim 1,
The polyamide composition comprises 100 ppb to 3100 ppm of zinc;
the polyamide composition comprises a delusterant comprising at least a portion of the phosphorus;
wherein the polyamide structure exhibits a Staphylococcus aureus reduction of at least 90% as measured by ISO 20743-13. According to claim 1,
A non-woven polyamide structure wherein the non-woven polyamide is melt spun, spunbonded, electrospun, solution spun or centrifugally spun. According to claim 1,
wherein no more than 20% of the fibers have a diameter greater than 700 nanometers. According to claim 1,
A non-woven polyamide structure, wherein the polyamide comprises nylon 66 or nylon 6/66. 100 ppb to 4000 ppm zinc dispersed in non-woven polyamide fibers; and
0 ppm to 2000 ppm phosphorus
As an antibacterial fiber having antibacterial properties,
the fibers have an average fiber diameter of less than 25 microns;
no more than 20% of the fibers have a diameter greater than 2 microns;
An antimicrobial fiber that exhibits Staphylococcus aureus reduction of 90% or more as measured by ISO 20743-13. According to claim 8,
wherein the weight ratio of zinc to phosphorus is at least 1.3:1, or less than 0.64:1. According to claim 8,
wherein the fibers have an average diameter of less than 20 microns. According to claim 8,
Wherein the antimicrobial fiber comprises 100ppb to 3100ppm of zinc. According to claim 8,
wherein the antimicrobial fiber has a zinc retention greater than 70% as measured by a dye bath test. According to claim 8,
The antibacterial fiber contains 100 ppb to 3200 ppm of zinc,
The antibacterial fiber comprises a matting agent containing at least a portion of the phosphorus,
wherein the antimicrobial fiber exhibits a Staphylococcus aureus reduction of at least 90% as measured by ISO 20743-13. According to claim 8,
wherein the nonwoven polyamide is melt spun, spunbond, electrospun, solution spun or centrifugally spun. According to claim 8,
wherein the polyamide comprises nylon 66 or nylon 6/66. A method for producing an antimicrobial nonwoven polyamide structure having permanent antibacterial properties, the method comprising:
preparing a precursor polyamide optionally comprising an aqueous monomer solution;
dispersing 100 ppb to 4000 ppm of zinc in the precursor polyamide;
dispersing 0 ppm to 2000 ppm of phosphorus in the precursor polyamide;
polymerizing the precursor polyamide to form a polyamide composition;
spinning the polyamide composition to form antimicrobial polyamide fibers; and
Forming the antimicrobial polyamide fibers into an antimicrobial nonwoven structure having a fiber diameter of less than 25 microns.
Including,
wherein no more than 20% of the fibers have a diameter greater than 2 microns. 17. The method of claim 16,
wherein the antimicrobial nonwoven polyamide has a zinc retention greater than 70% as measured by the dye bath test. 17. The method of claim 16,
wherein the weight ratio of zinc to phosphorus is at least 1.3:1 or less than 0.64:1. 17. The method of claim 16,
wherein the polyamide is melt spun by melt blowing through a die into a high velocity gaseous stream. delete 17. The method of claim 16,
wherein the polyamide is melt spun, spinbonded, electrospun, solution spun or centrifugally spun. non-woven polyamide fibers having an average fiber diameter of less than 25 microns; and
100 ppb to 4000 ppm zinc dispersed in the non-woven polyamide fibers
As a non-woven polyamide structure having antibacterial properties, including,
wherein no more than 20% of the fibers have a diameter greater than 2 microns;
A non-woven polyamide structure wherein the polyamide structure exhibits a Staphylococcus aureus reduction of at least 90% as measured by ISO 20743-13. A method for producing an antimicrobial nonwoven polyamide structure having antibacterial properties, the method comprising:
preparing a formulation comprising a polyamide, 100 ppb to 4000 ppm zinc dispersed in the polyamide, and 0 to 2000 ppm phosphorus dispersed in the polyamide;
spinning the formulation to form antimicrobial polyamide fibers having a fiber diameter of less than 25 microns, wherein no more than 20% of the fibers have a diameter greater than 2 microns; and
Forming the antimicrobial polyamide fibers into an antimicrobial non-woven polyamide structure
including, where
wherein the fiber is spun using a die pressure of less than 275 psig.

Images